Format IMMS#dump to display concurrent multi-users

New output format for `adb shell dumpsys input_method`:
```
Current Input Method Manager state:
  mSystemReady=...
  mInteractive=...
  mConcurrentMultiUserModeEnabled=...
  ENABLE_HIDE_IME_CAPTION_BAR=...
  mStylusIds=...
  mMenuControllerNew:
    isShowing: ...
  ...
  UserId=0
    Input Methods:
      InputMethod #0:
      ...
  UserId=10
    Input Methods:
      InputMethod #0:
      ...
  UserId=n
    ...
 [UserDataRepository]
 [ClientStates]
 [StartInputHistory]
 [SoftInputShowHideHistory]
 [ImeTrackerService]
```

Bug: 351912418
Flag: EXEMPT refactor dumpsys input_method
Test: m
Change-Id: I604784d6cb637334d933d20890998daa29181849