test_build_bundle fails for k8s rev 1920 (1.32/stable): cannot fulfill aws-integrator:rds-mysql (mysql interface)

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Filed by @canonical/solutions-qa

test_build_bundle fails for k8s rev 1920 (track: 1.32, stage: stable) because the bundle builder cannot fulfill the aws-integrator:rds-mysql endpoint (interface: mysql). All downstream tests are skipped as a result.

**Error:**
bundle_builder_x.bundle_builder.UncompletableBundleError: Could not build a complete valid bundle: Cannot fulfill charm endpoints: aws-integrator:rds-mysql

**Test plan:** integration/aws-integrator:aws/aws-integration/k8s:aws

**Affected environments:**
- juju:4/stable ubuntu:22.04 cmr/openstack/openstack (execution 536706)
- juju:3/stable ubuntu:22.04 cmr/openstack/openstack (execution 536704)

**Test Observer:** https://test-observer.canonical.com/#/charms/408049?testExecutionId=536706&testResultId=11630001

Start with integration/aws-integrator:aws/aws-integration/k8s:aws and reproduce test_build_bundle for k8s revision 1920 on the 1.32/stable track. Investigate the bundle_builder error for the aws-integrator:rds-mysql endpoint using the affected Juju/OpenStack executions. Done means the bundle builds completely and downstream tests are no longer skipped.

Written by the indexing model from the issue text.