Use String8/16 c_str [sensors]

Bug: 295394788
Test: make checkbuild
Change-Id: I09c5127f66c0ba1f7eef8951e3ab15f50f822d22
diff --git a/services/sensorservice/RecentEventLogger.cpp b/services/sensorservice/RecentEventLogger.cpp
index d7ca6e1..47fa8b3 100644
--- a/services/sensorservice/RecentEventLogger.cpp
+++ b/services/sensorservice/RecentEventLogger.cpp
@@ -83,7 +83,7 @@
         }
         buffer.append("\n");
     }
-    return std::string(buffer.string());
+    return std::string(buffer.c_str());
 }
 
 /**