Added UI Automation test for images to pdf functionality

[MannarAmuthan]

Added UI automation test for images to pdf functionality ,

• Workflow is currently upto Saving a File.
• File Is Not saving Successfully , because of some storage permission issue, so we won't assert that , test will check everything is working upto click save file.
• Need to fix it and add Assertion after saving a file.

Test run successfully in SDK 27,28 devices (Having some problems on 29,30 while getting some storage permissions, will fix it later ). If it is failing for first time, please re run it. Need to do some enhancements later.

How Has This Been Tested?

All the existing tests are passing and checkstyle also verified. Ran , ./gradlew assembleDebug assembleRelease and ./gradlew checkstyle

Checklist:

• My code follows the style guidelines of this project -> Yes
• I have performed a self-review of my own code -> Yes
• I have commented my code, particularly in hard-to-understand areas -> Yes
• I have made corresponding changes to the documentation -> Yes
• My changes generate no new warnings -> Yes

[codeclimate[bot]]

Code Climate has analyzed commit 3515d40c and detected 0 issues on this pull request.

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[Swati4star]

Closing due to inactivity.