fix: appcontext isSnapInstalled checks

[gomesalexandre]

Description

Does what it says on the box - we were casting an object into a Boolean which means checks would always return true, and "snap just installed" checks would never evaluate to true, meaning unless you refresh the app, snap installation would never trigger non-EVM accounts derivation/fetch.

Issue (if applicable)

closes #7376

Risk

High Risk PRs Require 2 approvals

None, this was blatantly wrong

What protocols, transaction types, wallets or contract interactions might be affected by this PR?

Testing

• Going from uninstalled snap to installed snap derives non-EVM accounts without needing a refresh

• Going from installed snap to uninstalled snap still clears accounts and trigger a refetch of EVM accounts only

• In Add Accounts modal, managing non-EVM chains when having the multichain snap installed is happy

• Managing accounts when not having the multichain snap installed is still disabled

Engineering

• ^

Operations

• 🏁 My feature is behind a flag and doesn't require operations testing (yet)

• ^

Screenshots (if applicable)

https://jam.dev/c/54a6c088-a295-4111-9fe6-5d17e0efc895

[woodenfurniture]

noted by @kaladinlight

Accounts/AddAccountModal.tsx: const isSnapInstalled = Boolean(useIsSnapInstalled())

[gomesalexandre]

noted by @kaladinlight

Accounts/AddAccountModal.tsx: const isSnapInstalled = Boolean(useIsSnapInstalled())

Here she is! 9c1cfcb

[0xApotheosis]

Works flawlessly.

✅ Going from uninstalled snap to installed snap derives non-EVM accounts without needing a refresh

✅ Going from installed snap to uninstalled snap still clears accounts and trigger a refetch of EVM accounts only

✅ In Add Accounts modal, managing non-EVM chains when having the multichain snap installed is happy

Matching prod behaviour in that account 0 can be "managed". but new accounts can't be added.

✅ Managing accounts when not having the multichain snap installed is still disabled