* Run dart command to update widget defaults

* Revert the tokens and the template

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Co-authored-by: Qun Cheng <quncheng@google.com>

Update Material tokens to 0.162

* Update to v0.158 of the token database.

* Update checkbox template

* Fix DatePickerTheme test

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Co-authored-by: Qun Cheng <quncheng@google.com>

* dart fix --apply

* manual fixes

* Updated to tokens v0.150.

* Updated with a reverted list_tile.dart.

* Bottom App Bar M3 background color fix

* update test

* test update

* remove whitespace

* Update IconButton unselected focused opacity

* Delete generated_plugins.cmake

* Added support for surfaceTintColor and shadowColor to the Dialog widgets.
* Updated the defaults for Material.shadowColor and Material.surfaceTint to allow turning off the features with a transparent color.
* Added support for shadowColor and surfaceTintColor for Drawer widget.

This reverts commit 79013b2b.

* Revert "Revert "Set `IconButton.visualDensity` default to `VisualDensity.standard` (#109349)" (#109421)"
Co-authored-by: Qun Cheng <quncheng@google.com>

This reverts commit 3070baf1.

* Set IconButton's visualDensity to standard
Co-authored-by: Qun Cheng <quncheng@google.com>

* Created IconButtonTheme and apply it to IconButton

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

* Added standard IconButton for M3 with new ButtonStyle field

* Added IconButton examples for standard, filled, filled_tonal, and outlined types
Co-authored-by: Qun Cheng <quncheng@google.com>

* Use `curly_braces_in_flow_control_structures` for `material`

* include test/material

* add back removed comments

This does a cleanup of the examples, removing all of the "section" markers and extra comments that we don't need anymore now that the samples are no longer in the source code. It also removes the --template arguments from the {@tool dartpad} and {@tool sample} directives, since those are no longer used. It converts two examples that I discovered were still embedded into linked examples in the examples folder.

I didn't delete the templates from the snippets config folder yet, because there are still embedded samples in the dart:ui package from the engine that use them. Once dart:ui no longer uses the templates, they can be removed.

I bumped the version of the snippets package to pick up a change that allows removal of the --template argument.

This extracts the sample code out from the API doc comments, and places them in separate files on disk, allowing running of the examples locally, testing them, and building of slightly larger examples.