fix: Remove broken failing test of @Deprecated DNS method

[vorburger]

Because as per #237 this test does not work anymore, see:

dnsTest(io.ipfs.api.APITest)  Time elapsed: 0.002 sec  <<< ERROR!
java.lang.RuntimeException:
IOException contacting IPFS daemon.
404 page not found

Trailer: null
        at io.ipfs.api.APITest.dnsTest(APITest.java:741)
Caused by: java.io.FileNotFoundException: http://127.0.0.1:5001/api/v0/dns?arg=ipfs.io&r=true
        at io.ipfs.api.APITest.dnsTest(APITest.java:741)

And on https://docs.ipfs.tech/reference/kubo/rpc/ there does not (anymore) appear to be a /api/v0/dns.

@ianopolous merge?