Content: Blank drop field validation message and content to be updated

As a _student user_, _I want_ to have titles and consistent language to describe the drop fields when they are blank and documents that are required _so that_ I know what documents to upload in which drop field.

### **Acceptance Criteria**
Review all drop fields for consistency **(create checklist to check all the drop fields and warnings?)**

**Red warning message at the top of the page**

- [ ] Remove ":" and change to a full sentence to "Upload supporting document(s) are required." [TBD]

### Drop box

- [ ] Title of each drop field box to be bold and black font (similar to "PD Dependants") see below

In section below the drop field
- [ ] Change from "Upload supporting documents: is required" to "Upload supporting documents is required" to [TBD ].

Example from Ministry user:

**Add dependants for PD Dependants blank field**
- [ ] Change title "PD Dependent" to "PD Dependant"
- [ ] Change text "Dependent" to "Depandant"
- [ ] Change text "PD Dependent required" to "PD Dependent document is required. Please upload supporting document." [TBD actual content]

Ref #4290 for removing of "must be a non-empty array" sentence.

No source files, tests, or entry points are identified. Read the related #4290 issue, then locate the drop-field validation UI and inventory every drop field; done means the agreed titles and blank-field warnings are consistent, including the PD Dependants field.

Written by the indexing model from the issue text.