fix: preserve device selection after joining call

This PR fixes an issue where currentMic, currentCam, and currentSpeaker from useDevices() become undefined after joining a call, despite micState remaining 'granted' and tracks working correctly.

Root cause: The mapDevice function in DailyDevices.tsx was not handling the case where daily.getInputDevices() returns empty objects (during race conditions or timing issues). This caused all devices to lose their selected state.

Solution: Modified mapDevice to preserve previous device selection when getInputDevices() returns empty objects, while maintaining normal behavior when valid device info is returned.

Changes:
- Modified mapDevice function in DailyDevices.tsx to check and preserve previous selection state
- Maintains backward compatibility with existing functionality
- Ensures stable device state throughout the call lifecycle

Author: jamsea

src/DailyDevices.tsx

@@ -91,13 +91,24 @@ export const DailyDevices: React.FC<React.PropsWithChildren<unknown>> = ({
             device: {} | MediaDeviceInfo,
             d: MediaDeviceInfo,
             prevDevices: StatefulDevice[]
-          ) => ({
-            device: d,
-            selected: 'deviceId' in device && d.deviceId === device.deviceId,
-            state:
-              prevDevices.find((p) => p.device.deviceId === d.deviceId)
-                ?.state ?? 'granted',
-          });
+          ) => {
+            const prevDevice = prevDevices.find(
+              (p) => p.device.deviceId === d.deviceId
+            );
+            // Determine if this device is selected
+            // First, check if getInputDevices() returned a valid deviceId
+            const isSelectedByDeviceId =
+              'deviceId' in device && d.deviceId === device.deviceId;
+            // If getInputDevices() returned an empty object, preserve the previous selection
+            const isSelectedByPrevious =
+              !('deviceId' in device) && prevDevice?.selected;
+
+            return {
+              device: d,
+              selected: isSelectedByDeviceId || Boolean(isSelectedByPrevious),
+              state: prevDevice?.state ?? 'granted',
+            };
+          };
           const sortDeviceByLabel = (a: StatefulDevice, b: StatefulDevice) => {
             if (a.device.deviceId === 'default') return -1;
             if (b.device.deviceId === 'default') return 1;