chore: Fix TS errors for EditGasFeeLegacyUpdate file

[devin-ai-integration]

Description

The aim of this chore is to achieve 100% TypeScript file coverage by fixing all TypeScript issues in the specified files.

/app/components/Views/confirmations/components/EditGasFeeLegacyUpdate/index.tsx:136-147

Changes made:

• Updated type assertions for gasFeeEstimate to handle different possible types (EthGasPriceEstimate, LegacyGasPriceEstimate, GasFeeEstimates)
• Added null coalescing operators to provide fallback values
• Improved type safety by explicitly handling different gas estimate types

Related issues

#10207

Manual testing steps

• yarn lint:tsc should yield no new or unexpected TypeScript errors

Pre-merge author checklist

• I've followed MetaMask 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.

[sonarqubecloud]

Quality Gate passed

Issues
0 New issues
0 Accepted issues

Measures
0 Security Hotspots
0.0% Coverage on New Code
0.0% Duplication on New Code

See analysis details on SonarCloud