In https://github.com/flutter/flutter/pull/82577, I landed a version
bump of package shelf and package flutter_template_images. This local
override should have been part of that patch but was missed in the
checkin.

The version bumps themselves happened in the previous patch; this just
ensures we don't accidentally 'upgrade' back to version 1.0.2.

This reverts commit c2aa193c.

This is in preparation to move the flutter artifacts to a more secure
location.

Bug:
  go/fxb/64576

This reverts commit ca2d7b3d.

* opt out the flutter tool

* oops EOF

* fix import

* Update tool_backend.dart

* Update daemon_client.dart

* fix more

This reverts commit 9d1d0cfe.

This reverts commit 7ba775a9.

* update pinned null safety deps

* run update-packages

* add http dep to devicelab package

* rerun update-packages

There have been some more additional reports of a missing 'package:characters' import after upgrading flutter. This has me concerned that our pub caching logic is incorrect. Instead of the tool attempting to guess when pub should be run, always delegate to pub.

Also takes an opportunity to fix the kernel snapshot depending on the .packages or package_config. Due to the generated: date field this causes extra rebuilds. Instead when pub get is run, write out an additional file with just the package contents and version.

Fixes #66777
Fixes #65723

Remove "This is taking a long time" progress timeout and TimeoutConfiguration.