The json input that is used with EF.MSISDN seems to be somewhat
ambigious. The original code accepts {"msisdn": "+4916012345678"}
only while the output is {"msisdn": [1, 1, "+4916012345678"]}. Lets
add a check and also accept the latter version.
Change-Id: I8f8dd68aac25d3fa3bc1aab06b855f8ec6640258
Related: OS#4963