[FLASK] Fix Snaps UI divider

[FrederikBolding]

Explanation

Fixes the Snaps UI divider by recreating it using a Box. It now has the same color as the snaps delineator, which was always intended.

[codecov]

Codecov Report

Merging #19919 (c6776aa) into develop (484dae3) will not change coverage.
The diff coverage is n/a.

@@           Coverage Diff            @@
##           develop   #19919   +/-   ##
========================================
  Coverage    69.54%   69.54%           
========================================
  Files          983      983           
  Lines        37162    37162           
  Branches      9965     9965           
========================================
  Hits         25843    25843           
  Misses       11319    11319           

Impacted Files	Coverage Δ
.../metamask-template-renderer/safe-component-list.js	100.00% <ø> (ø)

[metamaskbot]

Builds ready [c6776aa]

• builds: chrome, firefox
• builds (beta): chrome
• builds (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
  • common: 0, 1, 2, 3, 4, 5
  • content-script: 0
  • contentscript: contentscript
  • disable-console: disable-console
  • inpage: inpage
  • policy-load: policy-load
  • sentry-install: sentry-install
  • ui: 0, 1, 10, 11, 12, 2, 3, 4, 5, 6, 7, 8, 9

Page Load Metrics (1580 ± 52 ms)

Platform	Page	Metric	Min (ms)	Max (ms)	Average (ms)	StandardDeviation (ms)	MarginOfError (ms)
Chrome	Home	firstPaint	98	166	122	15	7
		domContentLoaded	1435	1848	1580	108	52
		load	1435	1848	1580	108	52
		domInteractive	1435	1848	1580	108	52

Bundle size diffs

• background: 0 bytes
• ui: 0 bytes
• common: 0 bytes