fix: Perf: Prevent MultipleNotifications rerenders

[darkwing]

Description

The MultipleNotifications component rerenders on a non-matching array of null values. This prevents that issue.

Related issues

Fixes:

Manual testing steps

1. Go to this page...

Screenshots/Recordings

Before

After

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[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 [52da8c7]

• 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, 8
  • 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 (1795 ± 93 ms)

Platform	Page	Metric	Min (ms)	Max (ms)	Average (ms)	StandardDeviation (ms)	MarginOfError (ms)
Chrome	Home	firstPaint	292	2138	1630	479	230
		domContentLoaded	1501	2118	1764	193	92
		load	1510	2136	1795	193	93
		domInteractive	25	108	45	24	11
		backgroundConnect	9	73	34	25	12
		firstReactRender	15	74	37	24	11
		getState	4	58	21	19	9
		initialActions	0	0	0	0	0
		loadScripts	1090	1544	1293	158	76
		setupStore	7	28	11	4	2
		uiStartup	1645	2474	2041	234	113

Bundle size diffs

• background: 0 Bytes (0.00%)
• ui: 42 Bytes (0.00%)
• common: 0 Bytes (0.00%)

[Prithpal-Sooriya]

Hmmm I need to do some reading, but now that this is an array of JSX elements, shouldn't we give these a key field to ensure that React effectively manages (reconciles) items in this list?