Make PromptView and PromptView.mPromptOptions visible for testing

[hdani9307]

I need the capability to test the displayed texts in espresso tests. Due to the visibility level is was not possible.

[codecov]

Codecov Report

Merging #193 (1997877) into master (2c48147) will increase coverage by 0.00%.
The diff coverage is 100.00%.

@@            Coverage Diff            @@
##             master     #193   +/-   ##
=========================================
  Coverage     92.53%   92.54%           
  Complexity      415      415           
=========================================
  Files            21       21           
  Lines          1300     1301    +1     
  Branches        150      150           
=========================================
+ Hits           1203     1204    +1     
  Misses           78       78           
  Partials         19       19           

Impacted Files	Coverage Δ	Complexity Δ
...terialtaptargetprompt/MaterialTapTargetPrompt.java	78.64% <100.00%> (+0.05%)	56.00 <0.00> (ø)

---

Continue to review full report at Codecov.

Legend - Click here to learn more
Δ = absolute <relative> (impact), ø = not affected, ? = missing data
Powered by Codecov. Last update 2c48147...1997877. Read the comment docs.

[sjwall]

Thank you for the PR, it will be in the next release