[Admin] Disclaimer about adjusting reimbursement report value to fit under cap

### Describe the problem

Currently, when a reimbursement report has a cap – there's usually a lot of back and forth between the operations team, YSWS org managers and the user. The user is always willing to fit the total reimbursement amount under the cap but due to Wise fee and currency fluctuations it always ends up crossing the limit.

The operations team sends the report back and asks them to fit it under the cap.

Example of back and forth: https://hcb.hackclub.com/reimbursement/reports/L8S2JV.

### Describe the feature/solution (optional)

Adding a disclaimer to the report while submitting that mentions the amount money sent will be capped at the report's limit and you may receive less than what is requested.

This is also approved by @LucyHackClub

Discussion for context: https://hackclub.slack.com/archives/GBXBFEED9/p1789557044836449

Start at the reimbursement report submission flow and review how the report cap is currently shown or enforced. Add a disclaimer before submission explaining that the amount sent may be capped at the report limit and may be less than requested; done means capped reports clearly show this warning to users.

Written by the indexing model from the issue text.