[eslint] turn of no-param-reassign
[eslint] turn of no-param-reassign

We do this often enough in our actual code that I don’t think it is 
worth the noise we create complaining about it. I feel it conditions 
people to ignore other stuff that does matter.

I also feel it is a valid thing to do and forcing people to use new 
variable names just to appease this rule is not helpful.

Here’s the docs about why the rule exists:
https://eslint.org/docs/rules/no-param-reassign

What say ye’all? Can we axe this?

Change-Id: Ib9e3c54e5a02d3bbc892d875448d71ae87b5e6c1
Reviewed-on: https://gerrit.instructure.com/167894
Tested-by: Jenkins
Reviewed-by: Jeremy Stanley <b3f594e10a9edcf5413cf1190121d45078c62290@instructure.com>
Reviewed-by: Clay Diffrient <9dff2e5c98626d20d2848250c411e8009465bb87@instructure.com>
QA-Review: Ryan Shaw <ea3cd978650417470535f3a4725b6b5042a6ab59@instructure.com>
Product-Review: Ryan Shaw <ea3cd978650417470535f3a4725b6b5042a6ab59@instructure.com>

sfu/canvas-lms,instructure/canvas-lms,instructure/canvas-lms,instructure/canvas-lms,sfu/canvas-lms,instructure/canvas-lms,instructure/canvas-lms,djbender/canvas-lms,djbender/canvas-lms,djbender/canvas-lms,sfu/canvas-lms,sfu/canvas-lms,sfu/canvas-lms,sfu/canvas-lms,instructure/canvas-lms,sfu/canvas-lms,instructure/canvas-lms,djbender/canvas-lms