Remove jsrsasign from npm app

[achamayou]

Removes the jsrsasign dependency from the tests/npm-app test app.

• Removed jsrsasign and @types/jsrsasign from tests/npm-app/package.json.
• Removed the /app/crypto endpoint (tests/npm-app/app.json, tests/npm-app/src/endpoints/crypto.ts), which existed solely as a canary check for jsrsasign's availability and is no longer needed now that the dependency is gone.
• Removed the corresponding GET /app/crypto assertion from tests/npm_tests.py.

[Copilot]

Pull request overview

This PR removes the jsrsasign dependency from the tests/npm-app package and updates the /app/crypto availability endpoint to check for the presence of CCF’s own @microsoft/ccf-app/crypto API instead. This keeps the npm test app aligned with the supported CCF crypto surface and reduces third-party crypto footprint in the test bundle.

Changes:

• Removed jsrsasign and @types/jsrsasign from tests/npm-app/package.json.
• Updated the /app/crypto availability check to use @microsoft/ccf-app/crypto (generateAesKey) rather than jsrsasign.

Custom instructions used:

• .github/copilot-instructions.md
• .github/instructions/reviewing.instructions.md

Reviewed changes

Copilot reviewed 2 out of 2 changed files in this pull request and generated no comments.

File	Description
tests/npm-app/src/endpoints/crypto.ts	Replaces the availability canary check to rely on @microsoft/ccf-app/crypto (CCF-provided crypto API).
tests/npm-app/package.json	Drops jsrsasign and its types from dependencies/devDependencies.