Don't animate ActivityIndicator when outputting to a file

[jflan-dd]

These changes are now available in 4.15.0

Long running loading/progress indicators create a lot of noisy output when an executable is outputting to Xcode's console, being captured to a file, or a piped to another command. e.g. #141

This PR skips writing the animated output of an ActivityIndicator if the console will not handle it well.

[jflan-dd]

@0xTim or @gwynne could you review this change when you get a chance?

[jflan-dd]

@0xTim or @gwynne is there someone that could review this PR?

[0xTim]

Thanks! Sorry for the delay, looks good to me

[codecov]

Codecov Report

All modified and coverable lines are covered by tests ✅

Project coverage is 54.26%. Comparing base (479a6af) to head (1c0ab67).
Report is 1 commits behind head on main.

Additional details and impacted files

@@            Coverage Diff             @@
##             main     #202      +/-   ##
==========================================
- Coverage   56.32%   54.26%   -2.07%     
==========================================
  Files         101      103       +2     
  Lines        4495     4515      +20     
==========================================
- Hits         2532     2450      -82     
- Misses       1963     2065     +102     

Files	Coverage Δ
...rces/ConsoleKitTerminal/Activity/ActivityBar.swift	62.50% <100.00%> (-12.50%)	⬇️
...onsoleKitTerminal/Activity/ActivityIndicator.swift	38.46% <100.00%> (-27.50%)	⬇️
Sources/ConsoleKitTerminal/Terminal/Console.swift	100.00% <100.00%> (ø)
Sources/ConsoleKitTerminal/Terminal/Terminal.swift	22.09% <100.00%> (-3.47%)	⬇️

... and 8 files with indirect coverage changes