[CCA] Convert modes.js into ES6 module.

Bug: 141518780
Test: Pass closure compiler check, tast run <DUT> 'camera.CCAUI*' on
both HALv1 and v3 devices.

Change-Id: Iac9a59809856274b86b0bca1c182576449d37133
Reviewed-on: https://chromium-review.googlesource.com/c/chromium/src/+/1988086
Commit-Queue: Kuo Jen Wei <inker@chromium.org>
Auto-Submit: Kuo Jen Wei <inker@chromium.org>
Reviewed-by: Shik Chen <shik@chromium.org>
Cr-Commit-Position: refs/heads/master@{#728477}

chrome/browser/resources/chromeos/camera/src/views/main.html

@@ -55,7 +55,7 @@
     <script type="module" src="../js/views/camera/recordtime.js"></script>
     <script type="module" src="../js/views/camera/review_result.js"></script>
     <script type="module" src="../js/views/camera/timertick.js"></script>
-    <script defer src="../js/views/camera/modes.js"></script>
+    <script type="module" src="../js/views/camera/modes.js"></script>
     <script type="module" src="../js/views/dialog.js"></script>
     <script type="module" src="../js/views/settings.js"></script>
     <script type="module" src="../js/views/warning.js"></script>