feat: add consent checkbox to onboarding metametrics page

[mirceanis]

Description

This adds a consent checkbox to the onboarding metametrics screen.
In this draft, the checkbox isn't wired to anything yet.

Related issues

Fixes: https://github.com/MetaMask/MetaMask-planning/issues/2526

Manual testing steps

1. Go to this page...

Screenshots/Recordings

Before

After

Pre-merge author checklist

• I’ve followed MetaMask 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.

[mirceanis]

I have read the CLA Document and I hereby sign the CLA

[metamaskbot]

Builds ready [2322921]

• 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, 2, 3, 4, 5, 6, 7, 8
  • content-script: 0
  • ui: 0, 1, 10, 2, 3, 4, 5, 6, 7, 8, 9

Page Load Metrics (1714 ± 514 ms)

Platform	Page	Metric	Min (ms)	Max (ms)	Average (ms)	StandardDeviation (ms)	MarginOfError (ms)
Chrome	Home	firstPaint	77	193	115	30	14
		domContentLoaded	9	85	20	18	9
		load	64	2787	1714	1071	514
		domInteractive	9	85	20	18	9

Bundle size diffs [🚨 Warning! Bundle size has increased!]

• background: 0 Bytes (0.00%)
• ui: 186 Bytes (0.00%)
• common: 184 Bytes (0.00%)

[mirceanis]

These changes have been cherry picked by another PR