Remove extra space at top of cmd-line example

[kwalrath]

Followup to #2266; see #2266 (review) for details.

[Nishikoh]

hi , @kwalrath .
If I will work on this issue, should I fix like next images?

current space

fix space

[kwalrath]

Actually, no. This bug is about a single sample, visible at https://dart.dev/tutorials/server/cmdline#overview-of-the-dcat-app-code. It seems to have an extra blank line at the top (above import 'dart:convert';), and I don't know why.

[Nishikoh]

@kwalrath
I understand.
I'll try to fix this issue.

[micpap25]

Looks like this issue was fixed with this merged, we can close this.

[kwalrath]

True. Thanks, @micpap25 and @Nishikoh!