feat: handle add fund auto check

[tuna1207]

Description

Auto check for user crypto balance and trigger subscription server validation if current subscription is paused and token balance is sufficient

Changelog

CHANGELOG entry: null

Related issues

Fixes:

Manual testing steps

1. Subscribe to shield using crypto
2. Have insufficient fund error for subscription
3. After adding fund, app should automatically trigger server validation for fund eligibility

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.

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Note

Automatically monitors crypto balance for paused Shield subscriptions and triggers server revalidation when sufficient funds are detected, with throttling and billing-cycle calculations.

• Shield subscription (UI):
  • Adds useShieldAddFundTrigger to auto-check user crypto balances for paused Shield subscriptions and trigger updateSubscriptionCryptoPaymentMethod + getSubscriptions when funds are sufficient.
  • Integrates trigger into ShieldSubscriptionProvider and types Redux dispatch to MetaMaskReduxDispatch.
  • Introduces throttling via new useThrottle hook (with comprehensive tests) to avoid frequent triggers.
• Pricing/Balances:
  • Leverages pricing data (useSubscriptionPricing, product plans, payment methods) and current EVM balances to determine fund sufficiency per selected token/chain.
• Shared:
  • Adds calculateSubscriptionRemainingBillingCycles in shared/modules/shield.ts using RECURRING_INTERVALS to compute remaining cycles used in balance checks.

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