ci: register plugin_runtime_views_unit-t in groups.json

Lint failure surfaced on PR #5690's CI run (job 73893199128) — the
chassis runtime-view test added in PR #5688 was never registered in
test/tap/groups/groups.json, and check_groups.py treats any unlisted
TAP source as a lint error.

Same group entry as the sibling plugin-chassis tests (plugin_dispatch
_unit-t, plugin_manager_unit-t, etc.):

    "plugin_runtime_views_unit-t" : [ "unit-tests-g1","@proxysql_min_version:4.0" ]

unit-tests-g1 is the standard host-only TAP group (no docker backend
required); the @proxysql_min_version:4.0 attribute keeps it from
running against pre-chassis builds.

Trivial fix that belongs on the same PR as the doc updates because
the lint failure is what surfaces on every PR opened against
plugin-chassis until this lands.

test/tap/groups/groups.json

@@ -202,6 +202,7 @@
   "plugin_prometheus_unit-t" : [ "unit-tests-g1","@proxysql_min_version:4.0" ],
   "plugin_query_hook_unit-t" : [ "unit-tests-g1","@proxysql_min_version:4.0" ],
   "plugin_registry_unit-t" : [ "unit-tests-g1","@proxysql_min_version:4.0" ],
+  "plugin_runtime_views_unit-t" : [ "unit-tests-g1","@proxysql_min_version:4.0" ],
   "prepare_statement_err3024-t" : [ "legacy-g1","mysql-auto_increment_delay_multiplex=0-g1","mysql-multiplexing=false-g1","mysql-query_digests=0-g1","mysql-query_digests_keep_comment=1-g1","mysql84-g1","mysql90-g1","mysql95-g1" ],
   "prepare_statement_err3024_async-t" : [ "legacy-g1","mysql-auto_increment_delay_multiplex=0-g1","mysql-multiplexing=false-g1","mysql-query_digests=0-g1","mysql-query_digests_keep_comment=1-g1","mysql84-g1","mysql90-g1","mysql95-g1" ],
   "prepare_statement_err3024_libmysql-t" : [ "legacy-g1","mysql-auto_increment_delay_multiplex=0-g1","mysql-multiplexing=false-g1","mysql-query_digests=0-g1","mysql-query_digests_keep_comment=1-g1","mysql84-g1","mysql90-g1","mysql95-g1" ],