Commit 68791f9ccc21548d27f1cf04d0b3270be4146b82 introduced regression.
It performed basicAuth check before built-in routes. It made impossible
to bypass basic authorization with `authKey` param.
This commit fixeds that issue and removes unneeded check. It also adds
integration tests for this case.
Related issue:
https://github.com/VictoriaMetrics/VictoriaMetrics/issues/7345
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Signed-off-by: f41gh7 <nik@victoriametrics.com>