Settings: learn more element should be combined into a single focusable element

Steps to reproduce:

1. Go to Settings > Accessibility > TalkBack > "Use service" or use the Volume key shortcut.
2. In the WordPress app, go to My Sites > Settings > More.
3. Swipe right to find the "Learn More" element.

Result: (48s)

This part of the Settings – More screen contains two elements that are focusable for TalkBack: (1) the text field, and (2) the learn more button. TalkBack reads the text of the first element (“You can…”) and finishes with “double tap to activate, double tap and hold to long press.” Double-tapping does nothing, however. Double tapping and holding opens a popup dialog. If the learn more button is focused, double tapping opens the same dialog. This could be improved by combining these two focusable elements into a single focusable element that opens the relevant dialog if activated.

_{/hat tip @mchowning for the report, internal reference: p77Llu-c0a-p2}

Start at the WordPress Android Settings > More screen and reproduce the issue with TalkBack using the steps in this report. Inspect the implementation of the Learn More text and button; done means they form one focusable element and activating it opens the relevant dialog.