Output Channel Drop-down does not track active channel on startup- with PR fix

[cleidigh]

Platforms Tested:
Insiders 5-30
Code 1.11.1 Stable

Windows 7
OS X Sierra
(should be all platforms)

Problem:
Output panel drop-down does not track current active output
if output channel is activated later , typically when
an extension output Channel is active (eg Git). Output
select box will show the default 0 index output (Tasks)

Steps to reproduce:

• Open code with git repository/workspace
• select Git output Channel
• close code
• reopen code
• Git output will be active but drop-down shows Tasks

Fixed with PR #27645

• always update active select box selection with setOptions call
  on any output channel update
• Tested on Windows 7, OS X

[isidorn]

Fixed via #27645