Fix smart_linkify_enabled flag.

The flag should only ensure that smart linkify calls behave in the
legacy way instead of totally disabling linkify.
Also, to keep the flag consistent with smart_selection_enabled and
smart_text_share_enabled flags, the flag should only disable the
SmartLinkify (i.e. Linkify.addLinksAsync) feature not TextClassifier
APIs (i.e. TextClassifier.generateLinks).

Also fixes issue with non-focusable TextViews by firing the primary
action instead of showing the floating toolbar. (b/73156794)

Bug: 75967597
Bug: 73156794
Test: bit FrameworksCoreTests:android.text.util.LinkifyTest
Test: bit CtsTextTestCases:android.text.util.cts.LinkifyTest
Test: bit FrameworksCoreTests:android.view.textclassifier.TextClassificationManagerTest
Test: bit CtsWidgetTestCases:android.widget.cts.TextViewTest
Test: bit FrameworksCoreTests:android.widget.TextViewActivityTest
Test: manual - checked behaviour turning flag on/off
Test: manual - checked behaviour with TextView.setFocusableInTouchMode(true/false)
Change-Id: I541f60161b9cd63ce7e57235607500f2fb0841e7