[interop] Add grpc-java 1.70.0 to client_matrix.py (grpc#38518)

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Closes grpc#38518

COPYBARA_INTEGRATE_REVIEW=grpc#38518 from shivaspeaks:master 032256c
PiperOrigin-RevId: 732047757

Author: shivaspeaks

tools/interop_matrix/client_matrix.py

@@ -461,6 +461,7 @@ def __init__(self, patch=[], runtimes=[], testcases_file=None):
             ("v1.67.1", ReleaseInfo()),
             ("v1.68.3", ReleaseInfo()),
             ("v1.69.1", ReleaseInfo()),
+            ("v1.70.0", ReleaseInfo()),
         ]
     ),
     "python": OrderedDict(