HFI Calc.: Add HFI threshold colour coding to PDF

**As a** *Plans/R/ZWCO* **I want** *to see the HFI colours in the PDF* **So That** *when I review the PDF to make decisions, the critical HFI thresholds jump out at me in the table*

**Additional Context**
- requested by Southeast and Kamloops in UXR and by email to PSU (June 7)
"I have found a glitch with the downloading the HFI PDF. The 3000, 4000, and I am sure 10,000 HFI values do not show in colour. As this is also a tool for situational awareness for the RWCO and PSO to identify areas of concern within the Fire Center the colours are important to stand out. It would also stand that the PFD should be look the same as the online platform." - SEFC Plans Section Officer

**Acceptance Criteria**
- [ ] Given I am using HFI Calc., When I download a PDF, Then any HFI values of 3,000+ are colour coded per the interface

**Definition of Done**
- Ready to Demo in Sprint Review
- Does what I have made have appropriate test coverage?
- Documentation and/or scientific documentation exists and can be found
- Peer Reviewed by 2 people on the team
- Manual testing of all PRs in Dev and Prod
- Merged

Start at the HFI Calc. PDF download entry point and compare its output with the online interface's HFI threshold colours. Trace where the PDF table values are rendered, then verify that values of 3,000 and above use the same colour coding and add appropriate test coverage.

Written by the indexing model from the issue text.