Feat/branding UI tests

[andrewleith]

Summary | Résumé

This PR adds UI tests for the branding features

Test suites

Branding settings

• [x] Passes a11y and HTML validation
• [x] Current branding can be seen
• [x] Current branding can be previewed

Choose GOC brandings

• [ ] Passes a11y and HTML validation
• [x] Cannot submit when no selection made
• [x] English-first logo is saved when selected
• [x] French-first logo is saved when selected

Choose from pool

• [x] Passes a11y and HTML validation
• [x] No selection made
• [x] Branding can be previewed
• [x] Branding can be saved
• [x] Org has no logos

Preview Branding

• [x] Passes a11y and HTML validation
• [x] GOC english-first brand can be previewed
• [x] GOC french-first brand can be previewed
• [ ] Custom logo can be previewed

Branding request tests

• [x] Passes a11y and HTML validation
• [x] Loads request branding page
• [x] Disallows submission when there is no data
• [x] Disallows submission when there is no image
• [x] Disallows submission when there is no brand name
• [x] Only allows pngs
• [x] Allows submission when all valid data provided
• [x] Displays branding preview
• [ ] Rejects malicious files