fix(config): stop exposing deprecated alias entries as Config properties (#9061)

A deprecated entry that only aliases a canonical option
(DD_PROFILING_EXPERIMENTAL_*, DD_TRACE_EXPERIMENTAL_RUNTIME_ID_ENABLED) must not
surface as its own Config property. helper.js deletes these from the shared
supported-configurations object after registering the deprecation; defaults.js
read the same object without the matching skip, so whether they became own
properties depended on which module required the JSON first. In v5 the config
spec builds defaults before helper, so Config gained DD_PROFILING_EXPERIMENTAL_*
keys the property-surface test flagged as unknown; v6 passed only because
major-overrides removes the entries outright.

Author: BridgeAR

packages/dd-trace/src/config/defaults.js

@@ -216,6 +216,14 @@ for (const [canonicalName, entries] of Object.entries(supportedConfigurations))
     )
   }
   for (const entry of entries) {
+    // A deprecated entry that only aliases a canonical option must not surface as
+    // its own Config property/default: the canonical entry already owns the value
+    // and the alias is resolved by helper.js. helper.js drops these from the shared
+    // supported-configurations object (after registering the deprecation), but that
+    // mutation is order-dependent on which module loads first. Skip here too so
+    // `defaults` is identical regardless of load order (it differed in v5, where
+    // major-overrides keeps these entries instead of deleting them outright).
+    if (entry.deprecated && entry.aliases) continue
     if (entry.sensitive) {
       sensitiveConfigurations.add(canonicalName)
     }
@@ -283,7 +291,7 @@ for (const [canonicalName, entries] of Object.entries(supportedConfigurations))
 
 // Replace the alias with the canonical property name.
 for (const [fullPropertyName, alias] of fallbackConfigurations) {
-  if (configurationsTable[alias].property) {
+  if (configurationsTable[alias]?.property) {
     fallbackConfigurations.set(fullPropertyName, configurationsTable[alias].property)
   }
 }