Adds Int Support competencies

Why is this change being made?

Support needs to add competencies to the new career matrices for Engineering. This MR adds the intermediate level ones.

Closes gitlab-com/support/support-team-meta#2423 (closed)

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sites/handbook/source/handbook/engineering/career-development/matrix/engineering/support/intermediate/_support_intermediate_leadership_competency.erb

-* Demonstrates a personal growth mindset by initiating pairings, completing bootcamps and building product and troubleshooting knowledge.
-* Understands support KPIs and optimizes personal workflow towards team achievement.
+* Demonstrates a personal growth mindset by initiating pairings, completing
+  bootcamps and building product and troubleshooting knowledge.
+* Understands support KPIs and optimizes personal workflow towards team
+  achievement.
+* Strives to work in accordance with documented support practices, processes
+  and policies, and proposes appropriate changes to improve them.