WIP update according to work for OSSM 3.1

<WIP>
DoDs:

Prepare sources:

1. sail-operator: source changed to downstream release-3.X branch with right SHA
2. QUESTION: should must-gather be changed to relerase branch? must-gather: source changed to downstream release-3.X branch with right SHA
3. istio: source_1 and source_2 changed to right upstream version with right SHA
4. proxy: source changed to right upstream version with right SHA

Switch operator to release branch:

1. Example: https://gitlab.cee.redhat.com/istio/cpaas/containers-midstream/-/commit/5ef6c45e321e05edc294088857393f1d02668acc

Code-freeze:

1. Replace development stage on code-freeze in openshift-servicemesh repo

Kiali: Kiali team shares operator and containers version to be attached to advisories

To be aware:
CI_ISTIO_UPSTREAM_VERSION_SANITIZED is used to get Istio version -> referenced istio repo must contain a version tag

<END WIP>

If the code freeze belongs to new minor version 3.x, ask Konflux repo admin to set branch ossm-3.x as default one and remove renovate.json file of previous OSSM version.

After code freeze, ask someone with Jira Admin privileges to do `Create new versions in Jira` subtask in this JIRA (see Sub-Tasks section)