fix(nomic,openai,perplexity): update pillow version to >= 12.1.1, <13.0.0 (#35254)

Updates the minimum Pillow version to address CVE-2026-25990 (HIGH
severity out-of-bounds write vulnerability affecting versions 10.3.0
through 12.1.0).

Changes:
langchain-nomic: pillow>=10.3.0,<13.0.0 → pillow>=12.1.1,<13.0.0
langchain-openai: pillow>=10.3.0,<13.0.0 → pillow>=12.1.1,<13.0.0
langchain-perplexity: pillow>=10.3.0,<13.0.0 → pillow>=12.1.1,<13.0.0
Safety: This is a minimum version bump within the existing constraint
range (<13.0.0), so no breaking changes are introduced.

CVE Details:
CVE-2026-25990: An out-of-bounds write may be triggered when loading a
specially crafted PSD image
Affected versions: 10.3.0 to <12.1.1
Fixed in: 12.1.1
Reference: https://nvd.nist.gov/vuln/detail/CVE-2026-25990

** Claude Helped me write this nice message **
The original findings was thanks to a Trivy scan

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Co-authored-by: Mason Daugherty <[email protected]>