CB-12645 : removed references to firefoxos

[audreyso]

Platforms affected

What does this PR do?

Removed references to firefoxos.

What testing has been done on this change?

Checklist

• Reported an issue in the JIRA database
• Commit message follows the format: "CB-3232: (android) Fix bug with resolving file paths", where CB-xxxx is the JIRA ID & "android" is the platform affected.
• Added automated test coverage as appropriate for this change.

[codecov-io]

Codecov Report

Merging #540 into master will increase coverage by 0.71%.
The diff coverage is n/a.

@@            Coverage Diff             @@
##           master     #540      +/-   ##
==========================================
+ Coverage   82.42%   83.13%   +0.71%     
==========================================
  Files          68       67       -1     
  Lines        5462     5338     -124     
  Branches     1072     1049      -23     
==========================================
- Hits         4502     4438      -64     
+ Misses        960      900      -60

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