Update git submodules

* Update docs/submodules/usecase-ui.git from branch 'master'
  to b7d48cb394ab3669a360ccc1672bdc196982abfa
  - Merge "Service Topology Changes"
  - Service Topology Changes
    
    Issue-ID: USECASEUI-419
    
    Signed-off-by: phani.y <yellela.nagaphanindra@huawei.com>
    Change-Id: I4f2d8a5a6309de92acd9384d499a285306036ebf
    
diff --git a/docs/submodules/usecase-ui.git b/docs/submodules/usecase-ui.git
index 771dcf4..b7d48cb 160000
--- a/docs/submodules/usecase-ui.git
+++ b/docs/submodules/usecase-ui.git
@@ -1 +1 @@
-Subproject commit 771dcf4ba2bf90a7da49bbec5d1a80c216c76de7
+Subproject commit b7d48cb394ab3669a360ccc1672bdc196982abfa