Update preference to set password field

The preference for the wifi tether password was having the input
type set incorrectly. This could lead to strange keyboard behavior
and the password being remembered by the keyboard which is bad.
This CL sets the appropriate field where needed.

Test: robotests
Bug: 77853620
Change-Id: I2a72fc863cd3779aed98a0df95500b652bb51cc8

tests/robotests/src/com/android/settings/widget/ValidatedEditTextPreferenceTest.java

@@ -116,7 +116,7 @@ public class ValidatedEditTextPreferenceTest {
         mPreference.onBindDialogView(mView);
 
         assertThat(editText.getInputType()
-                & (InputType.TYPE_TEXT_VARIATION_PASSWORD | InputType.TYPE_CLASS_TEXT))
+                & (InputType.TYPE_TEXT_VARIATION_VISIBLE_PASSWORD | InputType.TYPE_CLASS_TEXT))
                 .isNotEqualTo(0);
     }