Remove GitLab possessives from Growth docs

Two pages in the Growth docset contained the possessive form of
GitLab, which we shouldn't use for legal reasons.

doc/development/experiment_guide/index.md

@@ -25,7 +25,7 @@ In either case, an outcome of the experiment should be posted to the issue with
 Experiments' code quality can fail our standards for several reasons. These
 reasons can include not being added to the codebase for a long time, or because
 of fast iteration to retrieve data. However, having the experiment run (or not
-run) shouldn't impact GitLab's availability. To avoid or identify issues,
+run) shouldn't impact GitLab availability. To avoid or identify issues,
 experiments are initially deployed to a small number of users. Regardless,
 experiments still need tests.
 

doc/development/product_analytics/usage_ping.md

@@ -619,7 +619,7 @@ alt_usage_data(999)
 ### Prometheus Queries
 
 In those cases where operational metrics should be part of Usage Ping, a database or Redis query is unlikely
-to provide useful data. Instead, Prometheus might be more appropriate, since most of GitLab's architectural
+to provide useful data. Instead, Prometheus might be more appropriate, since most GitLab architectural
 components publish metrics to it that can be queried back, aggregated, and included as usage data.
 
 NOTE: