Migrate uses of ParameterizedMember::GetWithParamsIf* to GetIfItem and GetIfInnerList

Migrates all remaining callers of the deprecated GetWithParamsIfItem and
GetWithParamsIfInnerList methods to GetIfItem and GetIfInnerList, using
direct member access.

This follows up on cl/978493551.

Contains no intentional observable behavioral differences.

Tested:
    Tests have not finished; the CL author decided to mail
PiperOrigin-RevId: 979393784

quiche/quic/core/quic_stream_priority.cc

diff --git a/quiche/quic/core/quic_stream_priority.cc b/quiche/quic/core/quic_stream_priority.cc
index 2a1d041..149f10e 100644
--- a/quiche/quic/core/quic_stream_priority.cc
+++ b/quiche/quic/core/quic_stream_priority.cc
@@ -54,17 +54,14 @@
   bool incremental = HttpStreamPriority::kDefaultIncremental;
 
   for (const auto& [name, value] : *parsed_dictionary) {
-    const std::optional<
-        std::pair<const quiche::structured_headers::Item&,
-                  const quiche::structured_headers::Parameters&>>
-        item_and_params = value.GetWithParamsIfItem();
-    if (!item_and_params.has_value()) {
+    const quiche::structured_headers::ParameterizedItem* item =
+        value.GetIfItem();
+    if (!item) {
       continue;
     }
 
-    const quiche::structured_headers::Item& item = item_and_params->first;
     if (name == HttpStreamPriority::kUrgencyKey) {
-      const int64_t* parsed_urgency = item.GetIfInteger();
+      const int64_t* parsed_urgency = item->item.GetIfInteger();
       // Ignore out-of-range values.
       if (parsed_urgency &&
           *parsed_urgency >= HttpStreamPriority::kMinimumUrgency &&
@@ -72,7 +69,7 @@
         urgency = *parsed_urgency;
       }
     } else if (name == HttpStreamPriority::kIncrementalKey) {
-      if (const bool* parsed_incremental = item.GetIfBoolean()) {
+      if (const bool* parsed_incremental = item->item.GetIfBoolean()) {
         incremental = *parsed_incremental;
       }
     }