AC-664 Added Notification channel for higher API levels

[rishabh-997]

Description of what I changed

Issue I worked on

JIRA Issue: https://issues.openmrs.org/browse/AC-664

Checklist: I completed these to help reviewers :)

• My pull request only contains ONE single commit
  (the number above, next to the 'Commits' tab is 1).

• I have added tests to cover my changes. (If you refactored
  existing code that was well tested you do not have to add tests)

• All new and existing tests passed.

• My pull request is based on the latest changes of the master branch.

[codecov-commenter]

Codecov Report

Merging #795 into master will decrease coverage by 0.00%.
The diff coverage is 0.00%.

@@            Coverage Diff             @@
##           master     #795      +/-   ##
==========================================
- Coverage   13.87%   13.86%   -0.01%     
==========================================
  Files         227      227              
  Lines        9231     9236       +5     
  Branches      890      891       +1     
==========================================
  Hits         1281     1281              
- Misses       7851     7856       +5     
  Partials       99       99              

Impacted Files	Coverage Δ
...penmrs/mobile/services/ConceptDownloadService.java	0.00% <0.00%> (ø)
...g/openmrs/mobile/utilities/ApplicationConstants.kt	9.52% <0.00%> (-0.48%)	⬇️

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[f4ww4z]

Good work @rishabh-997