[ANCM In-proc] Improve handling of malformed warmup requests

[analogrelay]

Epic #8833

In some versions of Windows (RS1 or below), we get a malformed warm-up request that has missing data. We throw NullReferenceExceptions in that case, which is not ideal. We should investigate this further and try to make our logic more resiliant to these nulls, but only during these malformed warmup requests.

[analogrelay]

#6075 covered some of this.

[analogrelay]

When this is done, consider backporting.

[analogrelay]

Let's time box this a little as well. We know we can get some cheap wins with the changes we've already taken.

[analogrelay]

The 3.0 work is finished with #10053. Filing a new thing for backporting.