chore: clarifying comments for some github actions

[itsyoboieltr]

Description

This small PR adds some clarifying comments for some GitHub Actions, namely:

# For a `pull_request` event, the branch is `github.head_ref``.
# For a `push` event, the branch is `github.ref_name`.

to make sure the contributor is aware which variable corresponds to which event.

No functional changes, only cosmetic.

Related issues

Fixes:

Manual testing steps

1. Everything should work the same as before

Screenshots/Recordings

Not applicable

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.

[github-actions]

CLA Signature Action: All authors have signed the CLA. You may need to manually re-run the blocking PR check if it doesn't pass in a few minutes.

[Gudahtt]

LGTM!

[metamaskbot]

Builds ready [e1b6931]

• builds: chrome, firefox
• builds (flask): chrome, firefox
• builds (MMI): chrome
• builds (test): chrome, firefox
• builds (test-flask): chrome, firefox
• build viz: Build System
• mv3: Bundle Size Stats
• mv2: E2e Actions Stats
• storybook: Storybook
• typescript migration: Dashboard
• all artifacts
• bundle viz:

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

Page Load Metrics (1635 ± 129 ms)

Platform	Page	Metric	Min (ms)	Max (ms)	Average (ms)	StandardDeviation (ms)	MarginOfError (ms)
Chrome	Home	firstPaint	267	2743	1577	403	193
		domContentLoaded	1395	2725	1616	270	130
		load	1403	2743	1635	270	129
		domInteractive	23	98	35	19	9
		backgroundConnect	7	62	25	16	8
		firstReactRender	15	92	35	25	12
		getState	4	57	15	16	8
		initialActions	0	0	0	0	0
		loadScripts	1018	2284	1215	258	124
		setupStore	6	52	13	15	7
		uiStartup	1632	3035	1855	291	140

Bundle size diffs

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