fix: insufficient funds displays incorrect native token (#29828)

[matteoscurati]

Description

This PR addresses an issue where the "Insufficient funds" alert incorrectly displayed "ETH" as the native token, regardless of the actual network's native token
#28867. This was observed when users attempted to initiate a transaction on networks with a different native token, such as Polygon, where "POL" should be displayed instead of "ETH".

Related issues

Fixes: #28867

Manual testing steps

1. Select Polygon
2. Trigger a dapp tx with an account without funds (you can use these tests https://metamask.github.io/test-dapp/)
3. Click on the Alert
4. See POL as the token name

Screenshots/Recordings

Before

After

https://www.loom.com/share/8dd8001fc8d44da3b77e52a4877427f8

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 [f3d1168]

• 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, 13
  • content-script: 0
  • offscreen: 0

Page Load Metrics (1812 ± 74 ms)

Platform	Page	Metric	Min (ms)	Max (ms)	Average (ms)	StandardDeviation (ms)	MarginOfError (ms)
Chrome	Home	firstPaint	1547	2136	1813	146	70
		domContentLoaded	1499	2101	1786	144	69
		load	1507	2183	1812	155	74
		domInteractive	24	182	63	36	17
		backgroundConnect	6	100	26	25	12
		firstReactRender	16	74	39	24	12
		getState	5	50	15	13	6
		initialActions	0	0	0	0	0
		loadScripts	1039	1658	1320	137	66
		setupStore	6	54	16	17	8
		uiStartup	1766	2456	2097	187	90