Check if custom certs are enabled before use service cert

[codecov-commenter]

Codecov Report

All modified and coverable lines are covered by tests :white_check_mark:

Project coverage is 73.18%. Comparing base (058f198) to head (dcdcaa6).

Additional details and impacted files

```diff @@ Coverage Diff @@ ## main #979 +/- ## ========================================== + Coverage 73.01% 73.18% +0.17% ========================================== Files 106 106 Lines 6603 6604 +1 ========================================== + Hits 4821 4833 +12 + Misses 1486 1475 -11 Partials 296 296 ``` | [Flag](https://app.codecov.io/gh/grafana/tempo-operator/pull/979/flags?src=pr&el=flags&utm_medium=referral&utm_source=github&utm_content=comment&utm_campaign=pr+comments&utm_term=grafana) | Coverage Δ | | |---|---|---| | [unittests](https://app.codecov.io/gh/grafana/tempo-operator/pull/979/flags?src=pr&el=flag&utm_medium=referral&utm_source=github&utm_content=comment&utm_campaign=pr+comments&utm_term=grafana) | `73.18% <100.00%> (+0.17%)` | :arrow_up: | Flags with carried forward coverage won't be shown. [Click here](https://docs.codecov.io/docs/carryforward-flags?utm_medium=referral&utm_source=github&utm_content=comment&utm_campaign=pr+comments&utm_term=grafana#carryforward-flags-in-the-pull-request-comment) to find out more.

:umbrella: View full report in Codecov by Sentry.
:loudspeaker: Have feedback on the report? Share it here.