feat(IdPassForm): arrow keys and mouse wheel to cycle saved accounts (#241)

[lshw54]

What

WPF login form let users cycle through saved accounts using keyboard arrows and mouse wheel on the account TextBox. The SPA didn't have this.

Fix

• ArrowUp / ArrowDown on the account input cycles through savedAccountsForRegion
• Mouse wheel on the account input does the same
• Each cycle calls selectAccount() which prefills password / remember / autoLogin

Mirrors WPF behaviour reported in #241.

Closes #241