test: fix desktopCapturer restore-token specs on main (#55118)

The restore-token specs added in #54550 were written against a base that
predated #54439, which dropped chai/chai-as-promised/dirty-chai in favour
of vitest's own matchers and added the no-chai-assertions lint rule. On
main, `.to.be.eventually.rejectedWith()` and `.to.be.empty()` throw at
runtime and every chai chain trips lint. Switch them to vitest matchers.


Claude-Session: https://claude.ai/code/session_012AdLYu5PBMGgRbsE7frDma

Co-authored-by: Claude <noreply@anthropic.com>

spec/api-desktop-capturer.spec.ts

@@ -29,12 +29,12 @@ describe('desktopCapturer', { tags: ['serial'] }, () => {
 
   it('throws an error for an unknown persistMode', async () => {
     const promise = desktopCapturer.getSources({ types: getSourceTypes(), persistMode: 'forever' as any });
-    await expect(promise).to.be.eventually.rejectedWith(Error, 'Invalid options');
+    await expect(promise).rejects.toThrow('Invalid options');
   });
 
   it('throws an error for a non-string restoreToken', async () => {
     const promise = desktopCapturer.getSources({ types: getSourceTypes(), restoreToken: 42 as any });
-    await expect(promise).to.be.eventually.rejectedWith(Error, 'Invalid options');
+    await expect(promise).rejects.toThrow('Invalid options');
   });
 
   it('accepts persistMode and restoreToken and returns a restoreToken for each source', async () => {
@@ -44,21 +44,22 @@ describe('desktopCapturer', { tags: ['serial'] }, () => {
       persistMode: 'transient',
       restoreToken: ''
     });
-    expect(sources).to.be.an('array').that.is.not.empty();
+    expect(sources).toBeInstanceOf(Array);
+    expect(sources).not.toHaveLength(0);
     for (const source of sources) {
-      expect(source.restoreToken).to.be.a('string');
-      if (!isWayland) expect(source.restoreToken).to.be.empty();
+      expect(source.restoreToken).toBeTypeOf('string');
+      if (!isWayland) expect(source.restoreToken).toBe('');
     }
   });
 
   it('throws when restoreToken is passed without persistMode', async () => {
     const promise = desktopCapturer.getSources({ types: getSourceTypes(), restoreToken: 'token' });
-    await expect(promise).to.be.eventually.rejectedWith(Error, 'Invalid options');
+    await expect(promise).rejects.toThrow('Invalid options');
   });
 
   it('getRestoreToken returns an empty string for a source that has no token', () => {
-    expect(desktopCapturer.getRestoreToken('window:0:0')).to.equal('');
-    expect(desktopCapturer.getRestoreToken('not-a-source-id')).to.equal('');
+    expect(desktopCapturer.getRestoreToken('window:0:0')).toBe('');
+    expect(desktopCapturer.getRestoreToken('not-a-source-id')).toBe('');
   });
 
   it('getRestoreToken returns the restoreToken of a returned source', async () => {
@@ -66,9 +67,10 @@ describe('desktopCapturer', { tags: ['serial'] }, () => {
       types: getSourceTypes(),
       thumbnailSize: { width: 0, height: 0 }
     });
-    expect(sources).to.be.an('array').that.is.not.empty();
+    expect(sources).toBeInstanceOf(Array);
+    expect(sources).not.toHaveLength(0);
     for (const source of sources) {
-      expect(desktopCapturer.getRestoreToken(source.id)).to.equal(source.restoreToken);
+      expect(desktopCapturer.getRestoreToken(source.id)).toBe(source.restoreToken);
     }
   });