Misc improvements IV

[ohltyler]

Description

Continuation of #736.

• hide scrollbar by default for left nav, to keep width consistent across monitor resolutions and sizes
• multiple enhancements to the source data modal: increased vertical space for the json lines text editor, removed extra spacing below the cancel/confirm btns, and removed text wrapping, to more cleanly display the JSON line. Users can horizontally scroll to see the entire line, if it overflows. The vertical spacing was maximized such that on a laptop screen with browser at 100%, with 3 errors, there is no vertical overflow, to minimize any chance of the user not scrolling and missing the errors or what the expected format is
• increase vertical space for test query panel in Inspect
• remove overflow on delete modal from workflow list page

No relevant screenshots to add. Everything is the same, just minor tuning of the spacing and behavior to maximize workable space.

Check List

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[saimedhi]

LGTM. Will merge once tests pass.