Remove TODO comment in IMMS#applyImeVisibliity

As originally the TODO mentioned calling mWindowManagerInternal.hideIme
from IMMS that WM may not know which IME control target should apply
hideIme, since CL[1] has fixed with piping windowToken for hideSoftInput
to WM, so we can simply remove this TODO item.

[1]: Ia596a392eb73ae46debd097151c8c9a7edd59833

Bug: 246309664
Test: atest CtsInputMethodTestCases
Change-Id: I1e76138221bef8687507b4fcb18049d83215b5bf

services/core/java/com/android/server/inputmethod/InputMethodManagerService.java

@@ -4601,12 +4601,6 @@ public final class InputMethodManagerService extends IInputMethodManager.Stub
             }
             if (!setVisible) {
                 if (mCurClient != null) {
-                    // IMMS only knows of focused window, not the actual IME target.
-                    // e.g. it isn't aware of any window that has both
-                    // NOT_FOCUSABLE, ALT_FOCUSABLE_IM flags set and can the IME target.
-                    // Send it to window manager to hide IME from IME target window.
-                    // TODO(b/139861270): send to mCurClient.client once IMMS is aware of
-                    // actual IME target.
                     mWindowManagerInternal.hideIme(
                             mHideRequestWindowMap.get(windowToken),
                             mCurClient.mSelfReportedDisplayId);