Ensure plugin-proposal-private-methods is loose
Ensure plugin-proposal-private-methods is loose

This reduces noise in test output

Test plan:
 - All tests pass

flag=none

Change-Id: I15a9552915a75b75a1de32be40dfd3d38abd4439
Reviewed-on: https://gerrit.instructure.com/c/canvas-lms/+/277575
Tested-by: Service Cloud Jenkins <9144042a601061f88f1e1d7a1753ea3e2972119d@instructure.com>
Reviewed-by: Ahmad Amireh <a53a33601b8dd9d06ae9e50f1f30fbe957aba866@instructure.com>
QA-Review: Aaron Shafovaloff <d0ee6b99167c663aba7bc3efd806fe8d6cad437b@instructure.com>
Product-Review: Syed Hussain <1379c89cd1d253d3c5a299cc4d8f6002ada9d6b5@instructure.com>

sfu/canvas-lms,sfu/canvas-lms,sfu/canvas-lms,sfu/canvas-lms,sfu/canvas-lms,sfu/canvas-lms,sfu/canvas-lms