test: Cleanup extension e2e tests code

[chloeYue]

Description

As we have removed the confirmation screen legacy UI component, some e2e test code has become unused. This PR removes them.

Our approach is to never keep dead code in the test codebase, as it adds unnecessary complexity, making maintenance and debugging more difficult.

Related issues

Fixes:

Manual testing steps

Check code readability, make sure tests pass.

Screenshots/Recordings

Before

After

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.

[metamaskbot]

Builds ready [66d3f70]

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

Page Load Metrics (1927 ± 86 ms)

Platform	Page	Metric	Min (ms)	Max (ms)	Average (ms)	StandardDeviation (ms)	MarginOfError (ms)
Chrome	Home	firstPaint	289	2276	1835	395	190
		domContentLoaded	1579	2262	1903	178	86
		load	1590	2275	1927	179	86
		domInteractive	19	63	37	12	6
		backgroundConnect	12	74	29	19	9
		firstReactRender	17	94	40	26	12
		getState	6	62	24	21	10
		initialActions	0	1	0	0	0
		loadScripts	1103	1680	1379	153	74
		setupStore	9	59	22	19	9
		uiStartup	1827	2563	2219	204	98

Bundle size diffs

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

[DDDDDanica]

LGTM！

[metamaskbot]

Builds ready [537e91f]

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

Page Load Metrics (1816 ± 65 ms)

Platform	Page	Metric	Min (ms)	Max (ms)	Average (ms)	StandardDeviation (ms)	MarginOfError (ms)
Chrome	Home	firstPaint	289	2057	1730	352	169
		domContentLoaded	1575	2100	1787	136	65
		load	1621	2123	1816	135	65
		domInteractive	27	79	36	12	6
		backgroundConnect	14	63	37	18	8
		firstReactRender	17	81	32	21	10
		getState	6	86	25	25	12
		initialActions	0	1	0	0	0
		loadScripts	1104	1581	1310	127	61
		setupStore	8	57	15	13	6
		uiStartup	1839	2623	2113	189	91

Bundle size diffs

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