SERVER-84081 will add an AbortResult struct that the cleanup abort in the TXN API returns. This is used to provide the client with a write concern error in the case that a commit does not occur. To reduce code duplication, this struct should be merged with the CommitResult. 

The additional benefit of creating a general struct is that we can ensure that in the case an error occurs before a commit happens, we don't misleadingly prepend: "command error committing internal transaction :: caused by :: <error message>" to the error message.
Example:

Error: assert failed : {
 	"ok" : 0,
 	"errmsg" : "Command error committing internal transaction :: caused by :: Invalid value for ESCTokensV2 leaf tag 153",
 	"code" : 2,
 	"codeName" : "BadValue",
 }