Missing summary table in Github pull request comment

[hmG3]

Describe the bug
Github Comment Reporter doesn't render a summary markdown table as a PR comment if only one linter is enabled.

To Reproduce
Steps to reproduce the behavior:

1. Enable only one linter in the config file (for me it was RUBY_RUBOCOP but the actual linter doesn't matter)
2. Perform Megalinter run in Github Actions (flavor image doesn't matter) for a PR, so it finishes and prints the summary table in the console via Console Reporter. Notice the comment: [GitHub Comment Reporter] Posted summary as a comment on company/project #PR1
3. Navigate to the PR and see missing table in PR comment, despite the table exists in the console

Expected behavior
Github Comment Reporter should render the summary table for any number of enabled linters and any execution status.

Screenshots

Additional context
After investigating and debugging the current main branch, I found how the table should be generated. However the next line

megalinter/megalinter/utils_reporter.py

Line 71 in 21e87f7

table_content = str(writer) + os.linesep if len(table_data_raw) > 1 else ""

apparently has unexpected behavior in else case. If one linter is enabled, it overwrites the whole table content with empty string and thus we have the missing table. I tried to wrap os.linesep + if-else block in parentheses or even remove it - in both cases, it began to work as expected.

[Kurt-von-Laven]

Sounds like you already got it working, so if you are willing to open a pull request with your changes, that would be greatly appreciated!