Fix the workarounds for dependency problems of lifecycle-viewmodel(-ktx).

[yamasa]

androidx.fragment:fragment-ktx:1.4.0 depends on androidx.lifecycle:lifecycle-viewmodel-ktx:2.3.1, and
androidx.lifecycle:lifecycle-viewmodel-savedstate:2.4.0 depends on androidx.lifecycle:lifecycle-viewmodel:2.4.0.
But, lifecycle-viewmodel-ktx:2.3.1 and lifecycle-viewmodel:2.4.0 contain some classes with the same names, which leads to compilation errors.

Therefore, as a workaround, we explicitly added dependencies to androidx.lifecycle:lifecycle-viewmodel-ktx:2.4.0.

[yamasa]

https://issuetracker.google.com/issues/219545060
The original issue has been fixed in AndroidX Lifecycle 2.5.0.