refactor: Construct std::string outside critical section

There's no need to hold the mutex while constructing a `std::string`
from the `char` string.

Also use `inet_ntop` instead of the potentially thread-unsafe
`inet_ntoa` that might use a static buffer for the result.

This makes the `INet` case match the `INet6` case below.

src/lib/arch/unix/ArchNetworkBSD.cpp

@@ -590,10 +590,13 @@ std::string ArchNetworkBSD::addrToString(ArchNetAddress addr)
 
   switch (getAddrFamily(addr)) {
   case INet: {
+    char strAddr[INET_ADDRSTRLEN];
     const auto *ipAddr = TYPED_ADDR(struct sockaddr_in, addr);
-    std::scoped_lock lock{m_mutex};
-    std::string s = inet_ntoa(ipAddr->sin_addr);
-    return s;
+    {
+      std::scoped_lock lock{m_mutex};
+      inet_ntop(AF_INET, &ipAddr->sin_addr, strAddr, INET_ADDRSTRLEN);
+    }
+    return strAddr;
   }
 
   case INet6: {