op-mode: ipsec: T6407: fix profile generation

Commit 952b1656f51 ("ipsec: T5606: T5871: Use multi node for CA certificates")
added support for multiple CA certificates which broke the OP mode command
to generate the IPSec profiles as it did not expect a list and was rather
working on a string.

Now multiple CAs can be rendered into the Apple IOS profile.

(cherry picked from commit e6fe6e50a5c817e18c453e7bc42bb2e1c4b17671)