libnetd_server: avoid vector<const T>

A container of const T uses std::allocator<const T>, which was an
undocumented libc++ extension that has been removed.

See llvm/llvm-project#96319.

Bug: 349681543
Test: m libnetd_server
Change-Id: I1e97b0685fd94dc11f1c58c7fa05e1dd140d8172

Author: rprichard

server/TetherController.cpp

@@ -232,7 +232,7 @@ int TetherController::startTethering(bool usingLegacyDnsProxy, int num_addrs, ch
     char markStr[UINT32_HEX_STRLEN];
     snprintf(markStr, sizeof(markStr), "0x%x", fwmark.intValue);
 
-    std::vector<const std::string> argVector = {
+    std::vector<std::string> argVector = {
             "/system/bin/dnsmasq",
             "--keep-in-foreground",
             "--no-resolv",