Remove the dependency on IMM#isActive() from SearchView

Despite its name, InputMethodManager#isActive(View) internally aquires
IMM lock three times and may even trigger IME focus switching.

To make things simpler and more predictable,

  InputMethodManager#hasActiveInputConnectionInternal(View)

should be used instead.

The end result should be the same even with this commit.

Bug: 291826769
Test: atest CtsInputMethodTestCases:SearchViewTest
Change-Id: I0d061ac7c44650411eb49a2d2449482d4a2dce18