Fix prevent zero value for buffer line height (#30832)

Closes #30802 

Release Notes:

- Fixed issue where setting `buffer_line_height.custom` to 0 would cause
text to disappear

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Co-authored-by: Michael Sloan <michael@zed.dev>
a829281841Sergei Kartsev committed on 5/19/2025, 12:55:35 AM· committed by GitHubparent592568f
1 file changedLine totals unavailable