Make reset button accessible (#15257)

Make the reset button accessible by adding description in reset.

Closes #12044

---------

Co-authored-by: Dustin L. Howett <[email protected]>

Author: BenConstable9

src/cascadia/TerminalApp/ColorPickupFlyout.xaml

@@ -107,8 +107,7 @@
                         x:Uid="TabColorClearButton"
                         Grid.Column="0"
                         HorizontalAlignment="Stretch"
-                        Click="ClearColorButton_Click"
-                        Content="Reset" />
+                        Click="ClearColorButton_Click" />
                 <ToggleButton x:Name="CustomColorButton"
                               x:Uid="TabColorCustomButton"
                               Grid.Column="1"

src/cascadia/TerminalApp/Resources/en-US/Resources.resw

@@ -823,4 +823,8 @@
   <data name="ClosePaneToolTip" xml:space="preserve">
     <value>Close the active pane if multiple panes are present</value>
   </data>
+  <data name="TabColorClearButton.[using:Windows.UI.Xaml.Automation]AutomationProperties.FullDescription" xml:space="preserve">
+    <value>Reset tab color</value>
+    <comment>Text used to identify the reset button</comment>
+  </data>
 </root>