tests: fix helm upgrade test by correctly asserting whether KGO upgrades result in DataPlane image changes

[pmalek]

What this PR does / why we need it:

The test has been incorrectly checking whether the DataPlane has been patches while in reality it should check for its Deployment patch.

Additionally add a pretty print of said Deployment to verify its state if the test fails to extend this log:

=== FAIL: test/e2e TestE2E/TestHelmUpgrade/upgrade_from_1.3.0_to_current/DataPlane_deployment_is_not_patched_after_operator_upgrade (180.00s)
    test_helm_install_upgrade.go:404: DataPlane "154a4ae9-47e0-4422-95d4-717c7d8a43ee/gw-upgrade-130-current-tvthm-kjsvm" got patched but it shouldn't: <nil>
    test_helm_install_upgrade.go:404: 
        	Error Trace:	/home/runner/work/gateway-operator/gateway-operator/test/e2e/test_helm_install_upgrade.go:404
        	Error:      	Condition never satisfied
        	Test:       	TestE2E/TestHelmUpgrade/upgrade_from_1.3.0_to_current/DataPlane_deployment_is_not_patched_after_operator_upgrade

=== FAIL: test/e2e TestE2E/TestHelmUpgrade/upgrade_from_1.3.0_to_current (238.57s)

---

More importantly this PR changes the assertions around DataPlane deployments being patched between 1.2.3 -> 1.3.0 and 1.3.0 to latest because a default DP image change was introduced between those versions.

• from 1.2.3 to 1.3.0 default DataPlane image changed from 3.6 to 3.7
• from 1.3.0 to latest main default DataPlane image changed from 3.7 to 3.8