test: Fix invalid fixture builder

[Gudahtt]

Description

Two of the permission fixture builders were adding permissions for accounts that do not exist. They have been updated to only grant permissions for the selected account, which is the only account guaranteed to exist in the default fixture.

Related issues

This was extracted from #27847

Manual testing steps

See that E2E tests still pass

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
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Pre-merge reviewer checklist

• I've manually tested the PR (e.g. pull and build branch, run the app, test code being changed).
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[adonesky1]

LGTM

[Gudahtt]

This is the default selected account. I can update this in a separate PR to use the variable here instead.

[metamaskbot]

Builds ready [6ecf015]

• 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, 13
  • content-script: 0
  • offscreen: 0

Page Load Metrics (1610 ± 87 ms)

Platform	Page	Metric	Min (ms)	Max (ms)	Average (ms)	StandardDeviation (ms)	MarginOfError (ms)
Chrome	Home	firstPaint	250	2288	1497	427	205
		domContentLoaded	1420	2279	1594	182	88
		load	1439	2290	1610	181	87
		domInteractive	25	88	40	18	9
		backgroundConnect	5	64	18	19	9
		firstReactRender	15	81	43	26	13
		getState	4	50	10	12	6
		initialActions	0	0	0	0	0
		loadScripts	981	1686	1164	145	70
		setupStore	6	56	9	11	5
		uiStartup	1644	2479	1819	192	92

Bundle size diffs [🚀 Bundle size reduced!]

• background: -135 Bytes (-0.00%)
• ui: 0 Bytes (0.00%)
• common: 0 Bytes (0.00%)