[8.10] [Synthetics] Fix params sync is broken in non default space (#…

…166557) (#166604)

# Backport

This will backport the following commits from `main` to `8.10`:
- [[Synthetics] Fix params sync is broken in non default space
(#166557)](#166557)

<!--- Backport version: 8.9.7 -->

### Questions ?
Please refer to the [Backport tool
documentation](https://github.com/sqren/backport)

<!--BACKPORT
[{"author":{"name":"Shahzad","email":"[email protected]"},"sourceCommit":{"committedDate":"2023-09-18T10:47:00Z","message":"[Synthetics]
Fix params sync is broken in non default space
(#166557)","sha":"356d2a6028c590b4bacfdaeb8d8715057533195f","branchLabelMapping":{"^v8.11.0$":"main","^v(\\d+).(\\d+).\\d+$":"$1.$2"}},"sourcePullRequest":{"labels":["release_note:fix","Team:uptime","v8.10.0","v8.11.0"],"number":166557,"url":"https://github.com/elastic/kibana/pull/166557","mergeCommit":{"message":"[Synthetics]
Fix params sync is broken in non default space
(#166557)","sha":"356d2a6028c590b4bacfdaeb8d8715057533195f"}},"sourceBranch":"main","suggestedTargetBranches":["8.10"],"targetPullRequestStates":[{"branch":"8.10","label":"v8.10.0","labelRegex":"^v(\\d+).(\\d+).\\d+$","isSourceBranch":false,"state":"NOT_CREATED"},{"branch":"main","label":"v8.11.0","labelRegex":"^v8.11.0$","isSourceBranch":true,"state":"MERGED","url":"https://github.com/elastic/kibana/pull/166557","number":166557,"mergeCommit":{"message":"[Synthetics]
Fix params sync is broken in non default space
(#166557)","sha":"356d2a6028c590b4bacfdaeb8d8715057533195f"}}]}]
BACKPORT-->

Co-authored-by: Shahzad <[email protected]>

x-pack/plugins/synthetics/server/synthetics_service/synthetics_service.ts

@@ -608,7 +608,7 @@ export class SyntheticsService {
       await encryptedClient.createPointInTimeFinderDecryptedAsInternalUser<SyntheticsParams>({
         type: syntheticsParamType,
         perPage: 1000,
-        namespaces: spaceId ? [spaceId] : undefined,
+        namespaces: spaceId ? [spaceId] : [ALL_SPACES_ID],
       });
 
     for await (const response of finder.find()) {