fix: remove null assignment to fix strictNullChecks compile error in ObjectSerializer

baseNameToAttr was conditionally set to null when keepAllInAdditional is false,
which fails under strict: true. Always initialize to {} and skip population via
the existing keepAllInAdditional guard in the loop body.

Co-Authored-By: Claude Sonnet 4.6 <noreply@anthropic.com>

Author: charlie-zhang109

packages/datadog-api-client-v1/models/ObjectSerializer.ts

@@ -3343,7 +3343,7 @@ export class ObjectSerializer {
       // Single pass: build attributesBaseNames (for extra-key detection) and, when needed,
       // baseNameToAttr (for per-field typed deserialization preserving int64 precision).
       const attributesBaseNames: { [key: string]: string } = {};
-      const baseNameToAttr: { [key: string]: any } = keepAllInAdditional ? {} : null;
+      const baseNameToAttr: { [key: string]: any } = {};
       for (const attrName in attributesMap) {
         const baseName = attributesMap[attrName].baseName;
         attributesBaseNames[baseName] = "";

packages/datadog-api-client-v2/models/ObjectSerializer.ts

@@ -14359,7 +14359,7 @@ export class ObjectSerializer {
       // Single pass: build attributesBaseNames (for extra-key detection) and, when needed,
       // baseNameToAttr (for per-field typed deserialization preserving int64 precision).
       const attributesBaseNames: { [key: string]: string } = {};
-      const baseNameToAttr: { [key: string]: any } = keepAllInAdditional ? {} : null;
+      const baseNameToAttr: { [key: string]: any } = {};
       for (const attrName in attributesMap) {
         const baseName = attributesMap[attrName].baseName;
         attributesBaseNames[baseName] = "";