Include all file extensions in lint runs.

[dennisoelkers]

During the centralisation of the jest config module (#9548), we removed the --ext parameter to eslint in our yarn script definitions. Unfortunately, this makes eslint to lint .js, .ts & .tsx files only, due to eslint using js per default and merging it with ts/tsx from the overrides section of the eslint-config-graylog module.

In order to include jsx files again, this PR adds an empty overrides section including js & jsx explicitly to the eslint-config-graylog module.

[linuspahl]

Works as expected.