[lldb] Change interface of StructuredData::Array::GetItemAtIndexAsDictionary (#71961)

Similar to my previous patch (#71613) where I changed
`GetItemAtIndexAsString`, this patch makes the same change to
`GetItemAtIndexAsDictionary`.

`GetItemAtIndexAsDictionary` now returns a std::optional that is either
`std::nullopt` or is a valid pointer. Therefore, if the optional is
populated, we consider the pointer to always be valid (i.e. no need to
check pointer validity).

1 files changed, 4 insertions, 2 deletions

diff --git a/lldb/source/Plugins/Process/gdb-remote/GDBRemoteCommunicationClient.cpp b/lldb/source/Plugins/Process/gdb-remote/GDBRemoteCommunicationClient.cpp
index 04d98b9..2cf8c29 100644
--- a/lldb/source/Plugins/Process/gdb-remote/GDBRemoteCommunicationClient.cpp
+++ b/lldb/source/Plugins/Process/gdb-remote/GDBRemoteCommunicationClient.cpp
@@ -2649,10 +2649,12 @@ size_t GDBRemoteCommunicationClient::QueryGDBServer(
     return 0;
 
   for (size_t i = 0, count = array->GetSize(); i < count; ++i) {
-    StructuredData::Dictionary *element = nullptr;
-    if (!array->GetItemAtIndexAsDictionary(i, element))
+    std::optional<StructuredData::Dictionary *> maybe_element =
+        array->GetItemAtIndexAsDictionary(i);
+    if (!maybe_element)
       continue;
 
+    StructuredData::Dictionary *element = *maybe_element;
     uint16_t port = 0;
     if (StructuredData::ObjectSP port_osp =
             element->GetValueForKey(llvm::StringRef("port")))