fix(uss-tree): Fix getSessionNode from USS tree

[zFernand0]

Proposed changes

Check to see if the parent is null. If so, return this.

• Fix USS search filter fails on credential-less profiles #1805

Release Notes

Milestone: 2.0.2 (or higher)

Changelog: Fixed error "Cannot read getSessionNode of null"

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[zFernand0]

Please see build status in previous commit:

[rudyflores]

LGTM! Tested this with two profiles based on z/OSMF, these two being one with credentials on it and one without credentials on it on USS and it seems to be able to perform a filter search successfully and work as intended!

Thanks for this change @zFernand0 !

[JillieBeanSim]

LGTM! thanks for your work on this @zFernand0