Allow users to switch between manual and autoscale for fixed collections (#299)

- removed the `isFixed` check in both new and old settings tab so that the options to switch between manual and autoscale shows up for fixed collections
- updated the message below the text box to inform the users that the max RU for fixed collections is 10000
- updated validation rule so that the max RU cannot exceed 10000 for fixed collections for both autoscale and manual

src/Explorer/Controls/ThroughputInput/ThroughputInputComponentAutoscaleV3.html

@@ -119,6 +119,10 @@
       <span data-bind="text: spendAckText, attr: { for: spendAckId }"></span>
     </p>
     <!-- /ko -->
+
+    <!-- ko if: isFixed -->
+    <p>Choose unlimited storage capacity for more than 10,000 RU/s.</p>
+    <!-- /ko -->
   </div>
 
   <div data-bind="visible: !isAutoPilotSelected()">