[Button] Corner morph animation broken in ButtonGroup

[patzly]

Description: Hi, version 1.14.0-alpha06 was the last version where the corner morph animation plays as expected when buttons are used in a MaterialButtonGroup. Since 1.14.0-alpha07, the corner morph animation of buttons in a MaterialButtonGroup plays only two frames, which leads to a very abrupt experience. This was very like caused by ea9d250 or 9a8272d, I think.
In the screen recording of the latest Catalog app (1.14.0-alpha08) you can first see that the corner morph animation of standalone buttons is very smooth, like expected. Then when I switch to the Buttons Group page and tap on the buttons there (icon buttons are also affected), only two frames with either rounded corners or semi-rounded corners are played:

screen-20251223-225321-1766526787690.mp4

Expected behavior: The expected behavior is the pre-1.14.0-alpha07 behavior with smooth corner morph animations when buttons are placed inside of a MaterialButtonGroup.

Android API version: Android 16, API version 36

Material Library version: 1.14.0-alpha08

Device: Every emulator and every physical device

Thank you in advance for fixing this bug and for your great work!

[jayyaj12]

@patzly
I'd like to work on this issue :)
Can you assign it to me?

[patzly]

@jayyaj12 I'm sadly not a member of the MDC team so I cannot assign anybody.

[dsn5ft]

cc @pekingme