fix expected error case in tests

Author: hsubox76

packages/ai/src/models/generative-model.test.ts

@@ -553,7 +553,7 @@ describe('GenerativeModel dispatch logic', () => {
         mockChromeAdapter
       );
       await expect(model.generateContent('hello')).to.be.rejectedWith(
-        /On-device model is not available/
+        /on-device model is not available/
       );
       expect(mockChromeAdapter.generateContent).to.not.have.been.called;
       expect(makeRequestStub).to.not.have.been.called;
@@ -581,7 +581,7 @@ describe('GenerativeModel dispatch logic', () => {
         mockChromeAdapter
       );
       await expect(model.generateContentStream('hello')).to.be.rejectedWith(
-        /On-device model is not available/
+        /on-device model is not available/
       );
       expect(mockChromeAdapter.generateContent).to.not.have.been.called;
       expect(makeRequestStub).to.not.have.been.called;

packages/ai/src/requests/hybrid-helpers.test.ts

@@ -117,7 +117,7 @@ describe('callCloudOrDevice', () => {
       chromeAdapter.isAvailable.resolves(false);
       await expect(
         callCloudOrDevice(request, chromeAdapter, onDeviceCall, inCloudCall)
-      ).to.be.rejectedWith(/On-device model is not available/);
+      ).to.be.rejectedWith(/on-device model is not available/);
       expect(inCloudCall).to.not.have.been.called;
       expect(onDeviceCall).to.not.have.been.called;
     });