We can now DISCARD THE WARNING and wait until the authors of these packages deal with the new changes in flutter 3 to solve the problem and update their packages.
The developers of the packages are now catching up on these changes and there should be new versions of the affected packages soon.
Example of a package with this issue:
These warnings should not be breaking anything (just causing log
spam, for which we apologize; we plan to fix that in the next release,
we didn’t realize how big of an issue it would be). If your app no
longer works, that is unlikely to be related to this issue
reference:
https://github.com/flutter/flutter/issues/103561#issuecomment-1126416045