chore: remove unused usedNetworks state property from AppStateController

[cryptodev-2s]

Description

Building on the work done to remove the network modal in PR, this PR finalizes the process by completely removing the unused usedNetworks state property from AppStateController.

Related issues

Fixes:

Manual testing steps

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 [3c8bee1]

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

Page Load Metrics (2164 ± 116 ms)

Platform	Page	Metric	Min (ms)	Max (ms)	Average (ms)	StandardDeviation (ms)	MarginOfError (ms)
Chrome	Home	firstPaint	373	2754	1992	588	282
		domContentLoaded	1837	2694	2135	239	115
		load	1848	2761	2164	241	116
		domInteractive	28	88	41	16	8
		backgroundConnect	11	66	29	19	9
		firstReactRender	16	47	23	8	4
		getState	53	133	97	21	10
		initialActions	0	1	0	0	0
		loadScripts	1386	2207	1655	216	104
		setupStore	6	16	10	3	1
		uiStartup	2068	3076	2460	278	134

Bundle size diffs [🚀 Bundle size reduced!]

• background: -391 Bytes (-0.01%)
• ui: -40 Bytes (-0.00%)
• common: -240 Bytes (-0.00%)

[Gudahtt]

LGTM!

[metamaskbot]

Builds ready [593e03d]

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

Page Load Metrics (2008 ± 102 ms)

Platform	Page	Metric	Min (ms)	Max (ms)	Average (ms)	StandardDeviation (ms)	MarginOfError (ms)
Chrome	Home	firstPaint	269	2447	1704	694	333
		domContentLoaded	1664	2383	1975	188	90
		load	1669	2551	2008	213	102
		domInteractive	26	139	42	26	12
		backgroundConnect	7	161	32	34	17
		firstReactRender	16	111	28	21	10
		getState	71	223	110	37	18
		initialActions	0	1	0	0	0
		loadScripts	1271	1798	1522	152	73
		setupStore	6	84	16	21	10
		uiStartup	1883	3403	2333	349	167

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

• background: 535 Bytes (0.01%)
• ui: -40 Bytes (-0.00%)
• common: -240 Bytes (-0.00%)