PIR: Student can submit PIRs with same dates/overlapping dates (no overlap error)

**Describe the Bug**
Student: A student can submit two PIRs to the same school with the exact dates or overlapping dates

**Expected Behaviour**
Student should not be able to submit two PIRs at the same time with the same dates for the same PY

Student should not be able to submit two PIRs at the same time with overlapping dates for the same PY

They receive should receive the following error:

Inst:
They receive the same error message as above when they try to add a student to the same PIR

**Actual Behaviour**
Student does not receive an error message stating that their is a Program Information Record already submitted for those study dates.

Inst: The second app that had the same identical study dates remains (maybe non issue)

### Steps To Reproduce

Preconditions:
School has PIRs setup for two date ranges that are not overlapping Jan 5 2026 - April 24 2026 and May 5 2026 - Aug 28 2026)

Student tries to submit a PIR for with the exact same dates (e.g. Jan 5 2026 - April 24 2026 X 2)

1. Submit a PIR student application with Jan 5 2026 - April 24 2026
2. Submit a PIR student application with the same dates (warning message should display)
3. Institution: If there are two PIRs with the same date, attach a PIR to one (e.g. May 5 2026)
4. Institution: PIR with the original date Jan 5 2026 - Apr 24 2026 remains
5. Institution: Add 2nd PIR with the exact same dates as the first (May 5 2026) (error displays) (expected)

Staging:

Institution: