This reverts commit 1d2fa285.

* Add a snapAnimationDuration param in DraggableScrollableSheet

* snapAnimationDuration.inMilliseconds > 0

* Update draggable_scrollable_sheet.dart

* [flutter_tools] [dap] Add support for passing env variables to spawned processes

* Use named args

* Use in-memory fs and FakePlatform

* Pass filesystem style to MemoryFileSystem

* Remove periods from pub --help command descriptions

* Add trailing period consistently

* Remove added period from PackagesInteractiveGetCommand description

* Verify line ending for first line of command description

* Update _allowedTrailingPatterns to validate that lines end with only one period, bang, or colon

Refactor gen_defaults to support multiple generated code blocks in the same file independently. (#107278)