Fix: Rendering issue with codeblock and attachment combination

[Rohit3523]

Proposed changes

This PR addresses an issue where sending a codeblock with an attachment caused improper rendering. The root cause was the library appending an extra newline \n at the end of the string, which shows an unwanted blank line, resulting in a layout that differed from a standard codeblock.
Additionally, I have added a marginBottom to create a small gap between the attachment and codeblock

Issue(s)

None

How to test or reproduce

Send an attachment with codeblock

Screenshots

Before	After

Types of changes

• Bugfix (non-breaking change which fixes an issue)
• Improvement (non-breaking change which improves a current function)
• New feature (non-breaking change which adds functionality)
• Documentation update (if none of the other choices apply)

Checklist

• I have read the CONTRIBUTING doc
• I have signed the CLA
• Lint and unit tests pass locally with my changes
• I have added tests that prove my fix is effective or that my feature works (if applicable)
• I have added necessary documentation (if applicable)
• Any dependent changes have been merged and published in downstream modules

[diegolmello]

You missed the point on this issue.

See how both codeblock markdowns on the image are the same, but with different text styles?
That's what we're trying to fix.