fix(ui): display code snippets more appropriately

[bodinsamuel]

Describe your changes

Fixes https://linear.app/nango/issue/NAN-1322/unable-to-switch-to-curl-snippet-if-script-is-disabled Fixes https://linear.app/nango/issue/NAN-1321/remove-whitespace-from-api-ref-copypaste

• Remove whitespace from curl snippet
• Correctly return empty input (and handle empty object anyway just in case we have invalid data in the db)
• Fix valid way to pass --data

[linear[bot]]

NAN-1321 Remove whitespace from API ref copy/paste

NAN-1322 Unable to switch to curl snippet if script is disabled