BTS_Tests: add TC_{chan_act,encr_cmd}_a54 to control

Both testcases were introduced in 2021 [1], however they're not
executed on Jenkins because they're not present in control section.

Fixes: [1] I38e8a1cf15eb41a621b457b39024283a767c94be
Change-Id: Iebf6d14321b54e7ef261443aece03296540ebe92
diff --git a/bts/BTS_Tests.ttcn b/bts/BTS_Tests.ttcn
index b2d6383..f9361a0 100644
--- a/bts/BTS_Tests.ttcn
+++ b/bts/BTS_Tests.ttcn
@@ -8726,9 +8726,11 @@
 	execute( TC_chan_act_a51() );
 	execute( TC_chan_act_a52() );
 	execute( TC_chan_act_a53() );
+	execute( TC_chan_act_a54() );
 	execute( TC_encr_cmd_a51() );
 	execute( TC_encr_cmd_a52() );
 	execute( TC_encr_cmd_a53() );
+	execute( TC_encr_cmd_a54() );
 
 	execute( TC_err_rep_wrong_mdisc() );
 	execute( TC_err_rep_wrong_msg_type() );