test/system: Remove unnecessary --assumeyes

It shouldn't be necessary to use the --assumeyes option when creating a
Toolbx container, if the corresponding image is already present in the
local containers/storage image store.  It's harmful to test it with the
option, even when it shouldn't be needed, because it's off by default
and most users won't enable it.

Therefore, it's better to test the most common scenario that most users
will encounter.

#1536

test/system/101-create.bats

@@ -40,15 +40,15 @@ teardown() {
 @test "create: With a custom name (using option --container)" {
   pull_default_image
 
-  run "$TOOLBX" --assumeyes create --container "custom-containerName"
+  run "$TOOLBX" create --container "custom-containerName"
 
   assert_success
 }
 
 @test "create: With a custom image and name (using option --container)" {
   pull_distro_image fedora 34
 
-  run "$TOOLBX" --assumeyes create --container "fedora34" --image fedora-toolbox:34
+  run "$TOOLBX" create --container "fedora34" --image fedora-toolbox:34
 
   assert_success
 }