[1.x] chore: bump to pragmarx/google2fa v9

[joostdebruijn]

This PR updates the dependency pragmarx/google2fa to v9. This version contains a breaking change: the default secret key length has been increased from 16 to 32 characters for enhanced security. However, Laravel Fortify explicitly sets the default value for the generation of a secret key to 16:

fortify/src/TwoFactorAuthenticationProvider.php

Lines 44 to 47 in bd38202

	public function generateSecretKey(int $secretLength = 16)
	{
	return $this->engine->generateSecretKey($secretLength);
	}

Therefore, bumping to v9 is not a breaking change for Laravel Fortify.

In theory we could set the value to 32 as well, as in the migration the field two_factor_secret is of type TEXT so an increase in the length of the secret would not be an issue but there might be other side effects as well as mentioned in the release notes of pragmarx/google2fa. Such a change would be better for in a future 2.x-release.