Extension runs `conda install tensorboard` when upgrade is needed

[joyceerhl]

#15539 regressed upgrading tensorboard for conda users with an existing copy of tensorboard

H/T @lenisha for identifying the problem on a call together

[luabud]

@joyceerhl has this been fixed already?

[joyceerhl]

Yes I've submitted a fix, although I don't think the fix has been included in a stable release yet.

[luabud]

It should be out now :)