[GPU] Change default capacity of impls cache (openvinotoolkit#22200)

+ Change 1000 to 300 to reduce memory usage.

src/plugins/intel_gpu/include/intel_gpu/graph/program.hpp

@@ -306,7 +306,7 @@ struct program {
     // if subgraph can be optimized if it consists of only inputs and corresponding outputs
     bool _can_be_optimized;
     std::unique_ptr<ImplementationsCache> _impls_cache;
-    const size_t _impls_cache_capacity = 10000;
+    const size_t _impls_cache_capacity = 300;
     std::shared_ptr<ICompilationContext> _compilation_context;
     bool _loaded_from_cache = false;