enable 2-way sync with gatekeeper

[Thanhphan1147]

Add a field in CI to enable docs sync to discourse with gatekeeper

Checklist

• The charm style guide was applied
• The contributing guide was applied
• The changes are compliant with ISD054 - Managing Charm Complexity
• The documentation is generated using src-docs
• The documentation for charmhub is updated
• The PR is tagged with appropriate label (urgent, trivial, complex)

[github-actions]

Test coverage for 7de8f59

Name                    Stmts   Miss Branch BrPart  Cover   Missing
-------------------------------------------------------------------
src/agent_observer.py      42     24      4      0    39%   53-59, 69-87, 91-96
src/charm.py               53     12      6      2    73%   61->exit, 71, 83-95
src/charm_state.py         59     14      8      1    72%   95-96, 111-115, 154-156, 163, 172-174
src/service.py             92     47     14      1    43%   74-84, 89-93, 105->117, 119, 130-164, 172-176, 184-190
-------------------------------------------------------------------
TOTAL                     246     97     32      4    56%

Static code analysis report

Run started:2024-01-09 15:07:03.423650

Test results:
  No issues identified.

Code scanned:
  Total lines of code: 742
  Total lines skipped (#nosec): 0
  Total potential issues skipped due to specifically being disabled (e.g., #nosec BXXX): 0

Run metrics:
  Total issues (by severity):
  	Undefined: 0
  	Low: 0
  	Medium: 0
  	High: 0
  Total issues (by confidence):
  	Undefined: 0
  	Low: 0
  	Medium: 0
  	High: 0
Files skipped (0):