deps: bump requests to 2.33.0

[katsugtgz]

Updates requests to 2.33.0 to clear the advisories reported for the pinned 2.32.3.

Evidence:

• requirements.txt pinned requests==2.32.3
• osv-scanner reported PYSEC-2026-1872 (GHSA-9hjg-9r4m-mvj7) and PYSEC-2026-2275 (GHSA-gc5v-m9x4-r6x2) for requests 2.32.3
• updated version: 2.33.0

Validation:

• osv-scanner no longer reports those advisories for requests 2.33.0
• pip check passes with requests 2.33.0 installed alongside the repo's pinned urllib3 2.2.2, charset-normalizer 3.3.2, idna 3.7, certifi 2024.8.30
• full pip install -r requirements.txt does not resolve on a clean environment even before this change (mkl_fft==1.3.10 has no matching distribution outside conda), so the conda env from environment.yml remains the primary install path and is untouched

Scope: requirements.txt only.