Remove title case string for PWA install bubble text

This text used to be for a model dialog but is now used by a bubble.
Bubble dialogs don't use title text on any platform.

Before: https://bugs.chromium.org/p/chromium/issues/attachment?aid=419504&signed_aid=U0mvxY1dLrVi4TEDJKYtrA==&inline=1
After: https://bugs.chromium.org/p/chromium/issues/attachment?aid=419505&signed_aid=_YtJNSAFtjqMsLVgd1Foqg==&inline=1

Fixed: 1020310
Change-Id: Ia613fe934041fec7326550d8a438a4ab07f0d4c4
Reviewed-on: https://chromium-review.googlesource.com/c/chromium/src/+/1898905
Auto-Submit: Alan Cutter <alancutter@chromium.org>
Reviewed-by: Eric Willigers <ericwilligers@chromium.org>
Commit-Queue: Eric Willigers <ericwilligers@chromium.org>
Cr-Commit-Position: refs/heads/master@{#713284}

chrome/app/generated_resources.grd

@@ -2121,22 +2121,12 @@ are declared in tools/grit/grit_rule.gni.
       </if>
 
       <!-- "Install web app" confirmation bubble -->
-      <if expr="use_titlecase">
-        <message name="IDS_INSTALL_TO_OS_LAUNCH_SURFACE_BUBBLE_TITLE" desc="In Title Case: Title of the bubble for installing a web app to the operating system.">
-          Install App?
-        </message>
-        <message name="IDS_INSTALL_PWA_BUTTON_LABEL" desc="In Title Case: Text for button that installs a web app to the operating system.">
-          Install
-        </message>
-      </if>
-      <if expr="not use_titlecase">
       <message name="IDS_INSTALL_TO_OS_LAUNCH_SURFACE_BUBBLE_TITLE" desc="Title of the bubble for installing a web app to the operating system.">
         Install app?
       </message>
       <message name="IDS_INSTALL_PWA_BUTTON_LABEL" desc="Text for button that installs a web app to the operating system.">
         Install
       </message>
-      </if>
 
       <message name="IDS_BOOKMARK_APP_AX_BUBBLE_NAME_LABEL" desc="Text preceding the name of a bookmark app, read by spoken feedback.">
         Shortcut name