[Copy] Change to sentence case; remove superfluous colons; update English and French copy

[mnigh]

🤖 Resolves #12335.

👋 Introduction

This PR makes some copy fixes on the search request page and view request page, primarily issues of title case to sentence case, but also some other fixes to English copy and some French edits. It also removes all the colons from the labels in both languages (FilterBlock component) and updates some other text for consistency.

🧪 Testing

1. pnpm build:fresh
2. Navigate to Search request page
3. Verify English and French copy matches requested changes in linked issue
4. Navigate to View request page
5. Verify English and French copy matches requested changes in linked issue

📸 Screenshots

Search request page

English

French

View request page

English

French

Other

[esizer]

LGTM! 👍

[NienkeBr]

I noticed one more point I'd like to have updated, if I can still add it here.
On the search request page, could we change "Department/Hiring organization" and "Ministère/organisation d'embauche" to "Department or hiring organization" and "Ministère ou organisation d'embauche"?

[mnigh]

I noticed one more point I'd like to have updated, if I can still add it here. On the search request page, could we change "Department/Hiring organization" and "Ministère/organisation d'embauche" to "Department or hiring organization" and "Ministère ou organisation d'embauche"?

Screenshots