Add 'cache-control: no-store' header to DevTools server

Bug: https://github.com/flutter/devtools/issues/3896
Change-Id: I5cfc2e92716517a044a848339426feb827bb64cb
Reviewed-on: https://dart-review.googlesource.com/c/sdk/+/286100
Commit-Queue: Elliott Brooks <elliottbrooks@google.com>
Reviewed-by: Nate Bosch <nbosch@google.com>
Reviewed-by: Ben Konyi <bkonyi@google.com>

pkg/dds/lib/devtools_server.dart

@@ -282,7 +282,7 @@ class DevToolsServer {
     // Ensure browsers don't cache older versions of the app.
     server.defaultResponseHeaders.add(
       HttpHeaders.cacheControlHeader,
-      'max-age=0',
+      'no-store',
     );
 
     // Serve requests in an error zone to prevent failures