[FLASK] Fix eth_accounts permission for Snaps

[FrederikBolding]

Explanation

This PR fixes an issue with installing snaps that request eth_accounts.

To create the eth_accounts permission, we need the selected accounts from the UI, these are normally passed back in the result of the approval (see https://github.com/MetaMask/metamask-extension/blob/develop/ui/components/app/permission-page-container/permission-page-container.component.js#L90-L109).

With this PR we make that appropriate change and patch the SnapController to support this return value properly.

Manual Testing Steps

1. Create a template snap that uses eth_accounts
2. Install it and see that it successfully installs
3. Try develop and see that it fails to install there

[metamaskbot]

Builds ready [50dce11]

• builds: chrome, firefox, opera
• builds (beta): chrome, firefox, opera
• builds (flask): chrome, firefox, opera
• 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, 7
  • common: 0, 1, 2, 3, 4, 5, 6, 7, 8, 9
  • content-script: 0
  • contentscript: contentscript
  • disable-console: disable-console
  • inpage: inpage
  • policy-load: policy-load
  • sentry-install: sentry-install
  • ui: 0, 1, 2, 3, 4, 5, 6, 7, 8, 9

Page Load Metrics (2339 ± 74 ms)

Platform	Page	Metric	Min (ms)	Max (ms)	Average (ms)	StandardDeviation (ms)	MarginOfError (ms)
Chrome	Home	firstPaint	96	163	113	16	8
		domContentLoaded	1936	2777	2322	167	80
		load	2027	2777	2339	153	74
		domInteractive	1936	2777	2322	167	80

[metamaskbot]

Builds ready [de51497]

• builds: chrome, firefox, opera
• builds (beta): chrome, firefox, opera
• builds (flask): chrome, firefox, opera
• 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, 7
  • common: 0, 1, 2, 3, 4, 5, 6, 7, 8, 9
  • content-script: 0
  • contentscript: contentscript
  • disable-console: disable-console
  • inpage: inpage
  • policy-load: policy-load
  • sentry-install: sentry-install
  • ui: 0, 1, 2, 3, 4, 5, 6, 7, 8, 9

Page Load Metrics (2495 ± 142 ms)

Platform	Page	Metric	Min (ms)	Max (ms)	Average (ms)	StandardDeviation (ms)	MarginOfError (ms)
Chrome	Home	firstPaint	95	275	128	38	18
		domContentLoaded	1828	3115	2473	291	140
		load	1951	3211	2495	295	142
		domInteractive	1828	3115	2473	291	140

[FrederikBolding]

Closing in favor of #16161