[Follow up to #18534] MM importer is shown even when MM wallet is not created

[srirambv]

Description

MM importer is shown even when MM wallet is not created

Steps to Reproduce

1. Clean profile and open Brave Rewards page
2. Install MM from webstore, Only install do not create wallet
3. Open Brave wallet, shows MM importer

Actual result:

MM.Importer.mov

Expected result:

Should only show importer if wallet is created

Reproduces how often:

Easy

Brave version (brave://version info)

Brave	1.35.98 Chromium: 98.0.4758.74 (Official Build) (64-bit)
Revision	d0fe1ec4df090cd3eb02b591228505e12ea476e9-refs/branch-heads/4758@{#935}
OS	All

Version/Channel Information:

• Can you reproduce this issue with the current release? Yes when 1.35.x will be released which has the fix
• Can you reproduce this issue with the beta channel? Yes
• Can you reproduce this issue with the nightly channel? Yes

Other Additional Information:

• Does the issue resolve itself when disabling Brave Shields? NA
• Does the issue resolve itself when disabling Brave Rewards? NA
• Is the issue reproducible on the latest version of Chrome? NA

Miscellaneous Information:

cc: @darkdh

[darkdh]

handler.on(WalletPageActions.checkWalletsToImport.getType(), async (store) => {
  const braveWalletService = getWalletPageApiProxy().braveWalletService
  const cwResult =
    await braveWalletService.isExternalWalletInitialized(
      BraveWallet.ExternalWalletType.CryptoWallets)
  const mmResult =
    await braveWalletService.isExternalWalletInitialized(
      BraveWallet.ExternalWalletType.MetaMask)
  store.dispatch(WalletPageActions.setCryptoWalletsInstalled(cwResult.initialized))
  store.dispatch(WalletActions.setMetaMaskInstalled(mmResult.initialized))
})

mmResult from c++ has a false initialized value but somehow UI still display the button

[Uni-verse]

Verification completed using

Brave	1.37.105 Chromium: 100.0.4896.46 (Official Build) (x86_64) 
Revision	5ca33821b2211805855c77d334353d27c616a7ca-refs/branch-heads/4896@{#584}
OS	macOS Version 12.1 (Build 21C52)

• Verified MM importer not shown when MM wallet does not exist, only installed.