K8SPG-590 Add e2e test for database init sql functionality

[valmiranogueira]

CHANGE DESCRIPTION

Problem:
Add e2e test for database init sql functionality.

Cause:
Short explanation of the root cause of the issue if applicable.

Solution:
Short explanation of the solution we are providing with this PR.

CHECKLIST

Jira

• Is the Jira ticket created and referenced properly?
• Does the Jira ticket have the proper statuses for documentation (Needs Doc) and QA (Needs QA)?
• Does the Jira ticket link to the proper milestone (Fix Version field)?

Tests

• Is an E2E test/test case added for the new feature/change?
• Are unit tests added where appropriate?

Config/Logging/Testability

• Are all needed new/changed options added to default YAML files?
• Are all needed new/changed options added to the Helm Chart?
• Did we add proper logging messages for operator actions?
• Did we ensure compatibility with the previous version or cluster upgrade process?
• Does the change support oldest and newest supported PG version?
• Does the change support oldest and newest supported Kubernetes version?

[JNKPercona]

Test Name	Result	Time
backup-enable-disable	passed	00:06:43
custom-extensions	passed	00:11:20
custom-tls	passed	00:04:46
database-init-sql	passed	00:03:28
demand-backup	passed	00:25:52
finalizers	passed	00:04:29
init-deploy	passed	00:03:03
monitoring	passed	00:07:09
monitoring-pmm3	passed	00:08:15
one-pod	passed	00:05:41
operator-self-healing	passed	00:08:01
pgvector-extension	passed	00:02:40
pitr	passed	00:11:43
scaling	passed	00:04:36
scheduled-backup	passed	00:28:43
self-healing	passed	00:09:50
sidecars	passed	00:02:26
start-from-backup	passed	00:11:15
tablespaces	passed	00:07:14
telemetry-transfer	passed	00:03:15
upgrade-consistency	passed	00:05:45
upgrade-minor	passed	00:06:11
users	passed	00:03:31
We run 23 out of 23		03:06:08

commit: 07b014d
image: perconalab/percona-postgresql-operator:PR-1215-07b014d25