ci: Only check attributions on release candidates

[Gudahtt]

Description

The check-attributions workflow has been updated to only check on release candidates, as was initially intended.

Related issues

Fixes #29037

Manual testing steps

We could test this by creating a pretend release candidate, but that would mess up some of our other metrics/release automation. In this case it seems easier to test this by merging it, there are no significant negative consequences if it doesn't work as intended.

Screenshots/Recordings

N/A

Pre-merge author checklist

• I've followed MetaMask Contributor Docs and MetaMask Extension Coding Standards.
• I've completed the PR template to the best of my ability
• I’ve included tests if applicable
• I’ve documented my code using JSDoc format if applicable
• I’ve applied the right labels on the PR (see labeling guidelines). Not required for external contributors.

Pre-merge reviewer checklist

• I've manually tested the PR (e.g. pull and build branch, run the app, test code being changed).
• I confirm that this PR addresses all acceptance criteria described in the ticket it closes and includes the necessary testing evidence such as recordings and or screenshots.

[Gudahtt]

branches here refers to the target branch, rather than the HEAD branch. That's why this was running on cherry pick PRs.

See https://docs.github.com/en/actions/writing-workflows/choosing-when-your-workflow-runs/events-that-trigger-workflows#pull_request

[metamaskbot]

Builds ready [0209169]

• builds: chrome, firefox
• builds (beta): chrome
• builds (flask): chrome, firefox
• builds (MMI): chrome, firefox
• builds (test): chrome, firefox
• builds (test-flask): chrome, firefox
• build viz: Build System
• mv3: Background Module Init Stats
• mv3: UI Init Stats
• mv3: Module Load Stats
• mv3: Bundle Size Stats
• mv2: E2e Actions Stats
• code coverage: Report
• storybook: Storybook
• typescript migration: Dashboard
• all artifacts
• bundle viz:

  • background: 0, 1, 2, 3, 4, 5, 6
  • common: 0, 1, 10, 11, 12, 2, 3, 4, 5, 6, 7, 8, 9
  • content-script: 0
  • offscreen: 0
  • ui: 0, 1, 10, 11, 12, 13, 2, 3, 4, 5, 6, 7, 8, 9

Page Load Metrics (2056 ± 89 ms)

Platform	Page	Metric	Min (ms)	Max (ms)	Average (ms)	StandardDeviation (ms)	MarginOfError (ms)
Chrome	Home	firstPaint	1688	2487	2052	183	88
		domContentLoaded	1682	2479	2025	182	88
		load	1687	2494	2056	186	89
		domInteractive	26	85	45	18	8
		backgroundConnect	7	97	33	30	14
		firstReactRender	16	104	24	19	9
		getState	93	405	141	63	30
		initialActions	0	1	0	0	0
		loadScripts	1271	1971	1568	160	77
		setupStore	7	19	10	3	1
		uiStartup	1915	3026	2388	253	121

Bundle size diffs

• background: 0 Bytes (0.00%)
• ui: 0 Bytes (0.00%)
• common: 0 Bytes (0.00%)

[cryptodev-2s]

LGTM!

[itsyoboieltr]

LGTM!