fix: fix spinner display in NFT tab

[sahar-fehri]

Description

Fix spinner display in NFt tab.

No functional changes

Related issues

Fixes:

Manual testing steps

1. Go to nft tab
2. Spinner should be centered

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 [01ea1e1]

• 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
  • content-script: 0
  • offscreen: 0

Page Load Metrics (1809 ± 91 ms)

Platform	Page	Metric	Min (ms)	Max (ms)	Average (ms)	StandardDeviation (ms)	MarginOfError (ms)
Chrome	Home	firstPaint	445	2155	1659	440	211
		domContentLoaded	1476	2148	1780	187	90
		load	1501	2155	1809	189	91
		domInteractive	24	96	47	20	10
		backgroundConnect	8	77	29	21	10
		firstReactRender	14	76	41	25	12
		getState	4	66	17	18	9
		initialActions	0	44	2	10	5
		loadScripts	1047	1708	1314	171	82
		setupStore	8	60	18	16	8
		uiStartup	1714	2458	2076	218	105

Bundle size diffs

• background: 0 Bytes (0.00%)
• ui: 210 Bytes (0.00%)
• common: 0 Bytes (0.00%)