Update Sourcegraph Docker insiders images

[sourcegraph-bot]

This PR contains the following updates:

Package	Update	Change
index.docker.io/sourcegraph/cadvisor	digest	b58b694 -> 9da4e18
index.docker.io/sourcegraph/frontend	digest	2c52c5e -> 6a6215e
index.docker.io/sourcegraph/github-proxy	digest	f6a994a -> e5cd297
index.docker.io/sourcegraph/gitserver	digest	99b4479 -> 3d8b7bf
index.docker.io/sourcegraph/grafana	digest	96b78c8 -> 7026614
index.docker.io/sourcegraph/jaeger-agent	digest	f99f958 -> c60c358
index.docker.io/sourcegraph/jaeger-all-in-one	digest	c1800e3 -> 17b7ab2
index.docker.io/sourcegraph/precise-code-intel-worker	digest	5eeb914 -> 9b25342
index.docker.io/sourcegraph/prometheus	digest	5923ad2 -> 1f978b5
index.docker.io/sourcegraph/query-runner	digest	2efdc2d -> 55347d7
index.docker.io/sourcegraph/repo-updater	digest	ce3e6f7 -> 540141a
index.docker.io/sourcegraph/searcher	digest	01043b3 -> 0019c6d
index.docker.io/sourcegraph/symbols	digest	4869800 -> f63db70

Source: https://github.com/sourcegraph/sourcegraph/pull/18146

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