Code Scanning support for SARIF message string lookup in uploaded logs

The SARIF format supports the notion of indirect string lookups in its `message` object. Rather than directly providing a string in the `message.text` property, the indirect approach allows a specific set of other objects within the SARIF log to refer to the `message` object using its `id` property.

Currently, the CodeQL web service returns an error response when a log is uploaded which contains any `message` objects that don't provide a value in the `text` property:
`Error: Code Scanning could not process the submitted SARIF file: expected a result message`

The formal description of this feature and the decision tree for resolving the message string can be found here: [https://docs.oasis-open.org/sarif/sarif/v2.1.0/os/sarif-v2.1.0-os.html#_Toc34317468](https://docs.oasis-open.org/sarif/sarif/v2.1.0/os/sarif-v2.1.0-os.html#_Toc34317468)