Comment should not be applied to list* operations for server versions <4.4

The spec says that we should not send comments on server versions <4.4 for listIndexes, listDatabases, and listCollections operations. However, we have a bug in the `CommandOperation` class that will apply the comment to any command as long as it's of type "string", which overrides any operation-specific filtering of comments that is done prior to invoking executeCommand.

We missed this in testing because our custom format tests did not use the `comment:

` assertion in the corresponding event checks.

AC

• Remove the override logic in command.ts
• Fix tests to correctly assert the nonexistence of the property