insights: return repository metadata in ComputeText stream API

Created by: coury-clark

Code Insights requires results to have repository metadata so we can do operations such as sub-repo permissions filtering, repo permissions, and insight filtering. In the GraphQL API the ComputeText offers the repository metadata, but does not return the same in the streaming API.

query Run($query: String!) {
    compute(query: $query) {
        __typename
        ... on ComputeMatchContext {
            repository {
                name
                id
            }
            commit
            path
            matches {
                value
                environment {
                    variable
                    value
                }
              range{
                start {
                  line
                  character
                }
                end {
                  line
                  character
                }
              }
            }
        }
    ... on ComputeText {
      value
       }
    }
}

Streaming response: https://sourcegraph.com/github.com/sourcegraph/sourcegraph@409396a94f38279d147e996cd867e1faef0947c0/-/blob/enterprise/internal/compute/text_result.go?L3-6