fix: msal-react passes undefined to ssoSilent when no request provided

[lalimasharda]

When useMsalAuthentication is used with InteractionType.Silent and no authenticationRequest, instance.ssoSilent(undefined) was called, causing the silent flow to fail (issue #8382).

Changes

• useMsalAuthentication: Fall back to {} instead of undefined when no loginRequest is available, so ssoSilent always receives a valid request object
• MsalAuthenticationTemplate.spec.tsx: Updated test expectation to match the new {} fallback
• StandardController: Removed redundant prompt assignment from validRequest construction (already covered by the spread)
• hooks.md: Updated Silent interaction type note — request is now optional (empty object used as fallback), though providing loginHint, sid, or account is still strongly recommended

// Before
return instance.ssoSilent(loginRequest as SsoSilentRequest); // loginRequest could be undefined

// After
return instance.ssoSilent(loginRequest ? (loginRequest as SsoSilentRequest) : {});

[Copilot]

Pull request overview

This PR fixes a bug in MSAL React where InteractionType.Silent could end up calling instance.ssoSilent(undefined) when no authenticationRequest is provided, preventing the silent authentication flow from starting (issue #8382). It also includes a small cleanup in MSAL Browser around ssoSilent request construction.

Changes:

• Update useMsalAuthentication to pass {} (instead of undefined) to ssoSilent when no request is provided.
• Update the MsalAuthenticationTemplate test to expect an empty object for the ssoSilent request.
• Remove redundant prompt assignment/comment in msal-browser StandardController.ssoSilent request normalization.

Reviewed changes

Copilot reviewed 3 out of 3 changed files in this pull request and generated 2 comments.

File	Description
lib/msal-react/src/hooks/useMsalAuthentication.ts	Ensures ssoSilent is always invoked with a defined request object ({} fallback).
lib/msal-react/test/components/MsalAuthenticationTemplate.spec.tsx	Aligns test expectations with the new {} fallback behavior.
lib/msal-browser/src/controllers/StandardController.ts	Removes redundant prompt property assignment when building validRequest.