Add --no-preserve-encryption flag

* Add an option to send datasets with params or replicate
without preserving encryption
* Add a test case for the new functionality

Reviewed-by: Paul Dagnelie <paul.dagnelie@klarasystems.com>
Reviewed-by: Brian Behlendorf <behlendorf1@llnl.gov>
Reviewed-by: Alexander Motin <alexander.motin@TrueNAS.com>
Signed-off-by: Chris Jacobs <idefix2020dev@gmail.com>
Closes #18240

include/libzfs.h

@@ -844,6 +844,9 @@ typedef struct sendflags {
 
 	/* stream represents a partially received dataset */
 	boolean_t saved;
+
+	/* allow sending datasets with props, without preserving encryption */
+	boolean_t no_preserve_encryption;
 } sendflags_t;
 
 typedef boolean_t (snapfilter_cb_t)(zfs_handle_t *, void *);