This reverts commit 5fd259be.

This reverts commit 2be0d57f.

This reverts commit 9846fa51.

* opt out the flutter tool

* oops EOF

* fix import

* Update tool_backend.dart

* Update daemon_client.dart

* fix more

[flutter_tools] remove branch migration and standardize constructor style for version interface (#70058)

The tool observes a large number of unhandled exceptions during the file copy portion of flutter create. it is difficult to tell whether the permission issue is caused by the source/destination, or whether it is due to a bug in dart:io.

To work around this, implement a permission check for both the source and dest files. If either fails, the tool can exit with a more specific message.

If these checks pass, then perform the actual copy. If the copy fails, fallback to manually copying the bytes

package:http can throw a ClientException, which the crash reporter must catch or the tool will crash in the crash reporter. 3/4 crash on dev.