feat: Add accessibility support to the AuthenticationIdentityInputView - WPB-15221

[KaterinaWire]

WPB-15221 [iOS] Implement new authentication flow views - Identification View

Issue

In this PR I updated a UI according to a new design changes (@El-Fitz I hope you don't mind)
And updated the UI to support large fonts:

1. To ensure the main text grows vertically with .fixedSize(horizontal: false, vertical: true)
2. Shrink the text for the email text field header with .minimumScaleFactor(0.8)

Unfortunately, we can't do much with the placeholder except make it a custom text element.

Testing

Checklist

• Title contains a reference JIRA issue number like [WPB-XXX].
• Description is filled and free of optional paragraphs.
• Adds/updates automated tests.

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UI accessibility checklist

If your PR includes UI changes, please utilize this checklist:

• Make sure you use the API for UI elements that support large fonts.
• All colors are taken from WireDesign.ColorTheme or constructed using WireDesign.BaseColorPalette.
• New UI elements have Accessibility strings for VoiceOver.

[github-actions]

Test Results

  1 files   10 suites   32s ⏱️
107 tests 106 ✅ 1 💤 0 ❌
108 runs  107 ✅ 1 💤 0 ❌

Results for commit 2b178cc.

♻️ This comment has been updated with latest results.

[datadog-wireapp]

Datadog Report

Branch report: feat/acc-authentication-ui-identity-input
Commit report: 01e5eed
Test service: wire-ios-mono

✅ 0 Failed, 84 Passed, 1 Skipped, 14.97s Total Time

[samwyndham]

Looks good!