[Security Solution] kbn package for generic hook utils (#101976)

* Adds boilerplate for new hook-utils package

* Move existing, identified utils into our hook-utils package

Updates references, and fixes a few missing config that were preventing
packages from building.

* Extracts a common type and adds a little more JSdoc for clarity

* Adds new useObservable hook

Similar to useAsync (a nearly identical interface), this is meant to
wrap a thunk returning an observable, allowing conditional invocation
and progressive updates as the observable continues to emit.

* Remove orphaned test

This function (and its tests) were moved to the hook-utils package; this
was simply missed.

* Remove optional chaining from kbn package

The build system does not currently support these typescript features.
While a valid fix would also have been to build separate browser and
node targets a la #99390, the use here was very minimal and so changing
to a supported syntax was the most pragmatic fix.

* Update old reference in test file

Co-authored-by: Kibana Machine <42973632+kibanamachine@users.noreply.github.com>

docs/developer/getting-started/monorepo-packages.asciidoc

@@ -87,6 +87,7 @@ yarn kbn watch-bazel
 - @kbn/monaco
 - @kbn/rule-data-utils
 - @kbn/securitysolution-es-utils
+- @kbn/securitysolution-hook-utils
 - @kbn/securitysolution-io-ts-alerting-types
 - @kbn/securitysolution-io-ts-list-types
 - @kbn/securitysolution-io-ts-types