fix: allow flag and indicators in RFR

[JayDwee]

Summary

close #331

Checklist

• [x] This PR fixes an issue.
• [ ] This PR adds something new (e.g. new method or parameters).
• [ ] This PR is a breaking change (e.g. methods or parameters removed/renamed)
• [ ] This PR is not a code change (e.g. documentation, README, ...)

• [x] Have you tested the changes? (pytest & dpytest)
• [ x Have you followed PEP-8 for naming and styling?
• [x] Has your code been properly documented with RestructuredText docstrings?
• [x] Have you added your changes to CHANGELOG.md under the [Unreleased] heading?
• [ ] If your code added new bot commands, have you updated documentation.json?

• [x] All of this code is your own, or follows the author repo's licence.

[codecov[bot]]

Codecov Report

Merging #414 (ccdb0fa) into master (c6ace07) will increase coverage by 0.04%. The diff coverage is 93.02%.

@@            Coverage Diff             @@
##           master     #414      +/-   ##
==========================================
+ Coverage   87.35%   87.40%   +0.04%     
==========================================
  Files         123      123              
  Lines        8926     8961      +35     
==========================================
+ Hits         7797     7832      +35     
  Misses       1129     1129              

Flag	Coverage Δ
unittests	87.40% <93.02%> (+0.04%)	:arrow_up:

Flags with carried forward coverage won't be shown. Click here to find out more.

Impacted Files	Coverage Δ
koala/cogs/react_for_role/cog.py	49.01% <0.00%> (ø)
tests/tests_utils/utils.py	85.45% <75.00%> (+0.83%)	:arrow_up:
koala/cogs/react_for_role/core.py	68.18% <85.71%> (+0.14%)	:arrow_up:
koala/cogs/react_for_role/utils.py	100.00% <100.00%> (ø)
tests/cogs/react_for_role/test_cog.py	85.74% <100.00%> (+0.84%)	:arrow_up: