[codex] fix(ci): use release-please component branch names

[Palbahngmiyine]

What changed

• update the release-please PR SHA lookup to use the actual component-scoped branch name for beta

Why

The release workflow currently queries release-please--branches--beta, but release-please opens the PR from release-please--branches--beta--components--solapi. That causes Get PR head SHA to return empty, so the release PR validation jobs skip and the required Lint/Test contexts are never posted.

Impact

• restores release PR validation without changing the current beta release-please publishing flow
• keeps the supply-chain hardening work intact

Validation

• ruby -e 'require "yaml"; YAML.load_file(".github/workflows/release-please-beta.yml"); puts "ok"'
• git diff --check

[gemini-code-assist]

Note

Gemini is unable to generate a review for this pull request due to the file types involved not being currently supported.