test(smoke): add vector_enabled branch to role-group cm snapshot

When VECTOR_AGGREGATOR is set, the operator adds a vector.yaml key
to each role-group ConfigMap; the other four keys are unchanged.
The vector.yaml payload is the same across all five roles except
for a single `.role = "<role>"` line, so the content is declared
once via a jinja2 `{% set %}` block and substituted per role inside
the heredoc.

Verified against a live VECTOR_AGGREGATOR=vector-aggregator-discovery
cluster in namespace kuttl-test-distinct-camel.

Co-Authored-By: Claude Opus 4.7 (1M context) <noreply@anthropic.com>

Author: maltesander