[sanyamk23]

Fixes #2176

When blank=False (the default), the indent filter should not indent empty/blank lines. However, when first=True and the input is an empty string, the filter was incorrectly indenting the empty result.

This caused issues when rendering Jinja templates with empty blocks -- the closing tag would get extra indentation even when the block content was empty.

Before: {% filter indent(4, first=True) %}{% endfilter %} returned ' ' instead of ''
After: Returns '' as expected

[davidism]

https://palletsprojects.com/contributing/llm-ai