Fix Jest test failures caused by Node 24 / jsdom incompatibilities

[cliftonmcintosh]

What github issue is this PR for, if any?

Resolves #6825

What changed, and why?

Updated two Jest test files to be compatible with Node 24 and newer versions of jsdom. No production code was changed.

app/javascript/__tests__/two_minute_warning_session_timeout.test.js

Replaced Object.defineProperty(window, 'location', { writable: true, value: ... }) with delete window.location followed by a plain assignment. Newer versions of jsdom define location as non-configurable, causing the previous approach to throw TypeError: Cannot redefine property: location.

app/javascript/__tests__/validated_form.test.js

Updated assertions comparing CSS border values from '2px solid #ffc107' to '2px solid rgb(255, 193, 7)'. Newer versions of jsdom normalize CSS color values to rgb() notation when reading them back via jQuery's .css().

How is this tested? (please write rspec and jest tests!) 💖💪

The two previously failing test suites now pass:

npx jest app/javascript/__tests__/validated_form.test.js app/javascript/__tests__/two_minute_warning_session_timeout.test.js

[cliftonmcintosh]

@compwron

This fixes the lint failures that are occurring in some of the other PRs, including my case contact table PR.