[4.5.x] fix: force default value for endpoint weight

[mergify]

This is an automatic copy of pull request #10124 done by Mergify.

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Issue

https://gravitee.atlassian.net/browse/APIM-7954

Description

• in order to avoid having endpoint weight to 0, validation is done on service side and a protection is applied on gateway side

Additional context

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Cherry-pick of fda81d7 has failed:

On branch mergify/bp/4.5.x/pr-10124
Your branch is up to date with 'origin/4.5.x'.

You are currently cherry-picking commit fda81d72f1.
  (fix conflicts and run "git cherry-pick --continue")
  (use "git cherry-pick --skip" to skip this patch)
  (use "git cherry-pick --abort" to cancel the cherry-pick operation)

Changes to be committed:
	modified:   gravitee-apim-definition/gravitee-apim-definition-jackson/src/main/java/io/gravitee/definition/jackson/datatype/api/deser/EndpointDeserializer.java
	modified:   gravitee-apim-gateway/gravitee-apim-gateway-core/src/main/java/io/gravitee/gateway/core/loadbalancer/WeightedLoadBalancer.java
	modified:   gravitee-apim-gateway/gravitee-apim-gateway-core/src/main/java/io/gravitee/gateway/reactive/core/v4/endpoint/loadbalancer/WeightedLoadBalancer.java
	new file:   gravitee-apim-gateway/gravitee-apim-gateway-core/src/test/java/io/gravitee/gateway/core/loadbalancer/WeightedRoundRobinLoadBalancerTest.java
	modified:   gravitee-apim-gateway/gravitee-apim-gateway-core/src/test/java/io/gravitee/gateway/reactive/core/v4/endpoint/loadbalancer/WeightedRoundRobinLoadBalancerTest.java
	modified:   gravitee-apim-rest-api/gravitee-apim-rest-api-service/src/test/java/io/gravitee/rest/api/service/v4/impl/validation/EndpointGroupsValidationServiceImplTest.java

Unmerged paths:
  (use "git add/rm <file>..." as appropriate to mark resolution)
	deleted by us:   gravitee-apim-definition/gravitee-apim-definition-model/src/main/java/io/gravitee/definition/model/v4/endpointgroup/AbstractEndpoint.java
	both modified:   gravitee-apim-rest-api/gravitee-apim-rest-api-service/src/main/java/io/gravitee/rest/api/service/v4/impl/validation/EndpointGroupsValidationServiceImpl.java

To fix up this pull request, you can check it out locally. See documentation: https://docs.github.com/en/pull-requests/collaborating-with-pull-requests/reviewing-changes-in-pull-requests/checking-out-pull-requests-locally

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📚  View the storybook of this branch here

[mergify]

Cherry-pick of fda81d7 has failed:

On branch mergify/bp/4.5.x/pr-10124
Your branch is up to date with 'origin/4.5.x'.

You are currently cherry-picking commit fda81d72f1.
  (fix conflicts and run "git cherry-pick --continue")
  (use "git cherry-pick --skip" to skip this patch)
  (use "git cherry-pick --abort" to cancel the cherry-pick operation)

Changes to be committed:
	modified:   gravitee-apim-definition/gravitee-apim-definition-jackson/src/main/java/io/gravitee/definition/jackson/datatype/api/deser/EndpointDeserializer.java
	modified:   gravitee-apim-gateway/gravitee-apim-gateway-core/src/main/java/io/gravitee/gateway/core/loadbalancer/WeightedLoadBalancer.java
	modified:   gravitee-apim-gateway/gravitee-apim-gateway-core/src/main/java/io/gravitee/gateway/reactive/core/v4/endpoint/loadbalancer/WeightedLoadBalancer.java
	new file:   gravitee-apim-gateway/gravitee-apim-gateway-core/src/test/java/io/gravitee/gateway/core/loadbalancer/WeightedRoundRobinLoadBalancerTest.java
	modified:   gravitee-apim-gateway/gravitee-apim-gateway-core/src/test/java/io/gravitee/gateway/reactive/core/v4/endpoint/loadbalancer/WeightedRoundRobinLoadBalancerTest.java
	modified:   gravitee-apim-rest-api/gravitee-apim-rest-api-service/src/test/java/io/gravitee/rest/api/service/v4/impl/validation/EndpointGroupsValidationServiceImplTest.java

Unmerged paths:
  (use "git add/rm <file>..." as appropriate to mark resolution)
	deleted by us:   gravitee-apim-definition/gravitee-apim-definition-model/src/main/java/io/gravitee/definition/model/v4/endpointgroup/AbstractEndpoint.java
	both modified:   gravitee-apim-rest-api/gravitee-apim-rest-api-service/src/main/java/io/gravitee/rest/api/service/v4/impl/validation/EndpointGroupsValidationServiceImpl.java

To fix up this pull request, you can check it out locally. See documentation: https://docs.github.com/en/pull-requests/collaborating-with-pull-requests/reviewing-changes-in-pull-requests/checking-out-pull-requests-locally