Roll Packages from a2f4ce0a5057 to 23e56af4a622 (5 revisions) (#145470)

https://github.com/flutter/packages/compare/a2f4ce0a5057...23e56af4a622

2024-03-19 43054281+camsim99@users.noreply.github.com [camerax] Update README to encourage users to opt in (flutter/packages#6352)
2024-03-19 dawidope@gmail.com [flutter_markdown] Allow for custom block element (flutter/packages#5815)
2024-03-19 10687576+bparrishMines@users.noreply.github.com [pigeon] Adds Dart implementation of ProxyApi (flutter/packages#6043)
2024-03-19 43054281+camsim99@users.noreply.github.com [camerax] Implements `setFocusMode` (flutter/packages#6176)
2024-03-19 engine-flutter-autoroll@skia.org Roll Flutter from f217fc17 to d31a85ba (23 revisions) (flutter/packages#6356)

If this roll has caused a breakage, revert this CL and stop the roller
using the controls here:
https://autoroll.skia.org/r/flutter-packages-flutter-autoroll
Please CC flutter-ecosystem@google.com,rmistry@google.com on the revert to ensure that a human
is aware of the problem.

To file a bug in Flutter: https://github.com/flutter/flutter/issues/new/choose

To report a problem with the AutoRoller itself, please file a bug:
https://issues.skia.org/issues/new?component=1389291&template=1850622

Documentation for the AutoRoller is here:
https://skia.googlesource.com/buildbot/+doc/main/autoroll/README.md

bin/internal/flutter_packages.version

-a2f4ce0a50570a623e54788901314b5f8352c0cc
+23e56af4a622ded77838958ffccc89cf4aaa23b2