Release Plan update for Sync26

[rartych]

What type of PR is this?

• subproject management

What this PR does / why we need it:

The release-plan.yaml file requires updates to align with the Sync26 meta-release cycle and prepare for the r4.1 release.

• Set meta_release: Sync26.
• Increment target_release_tag to r4.1.
• Set target_release_type to pre-release-rc.
• Update dependencies:
  • commonalities_release: r4.3.
  • identity_consent_management_release: r4.2.
• Update the call-forwarding-signal API:
  • Version: 0.5.0.
  • Status: rc.

Which issue(s) this PR fixes:

Fixes #

Special notes for reviewers:

Changelog input

 Plan update for release candidate r4.1

[bigludo7]

Thanks Rafal