[web_server_base] Reduce sizeof(WebServerBase) by 4 bytes

Change initialized_ from int to uint8_t. This field is a refcount
that only reaches 1-2 in practice. The smaller type packs next to
port_ (uint16_t), shrinking the first field group from 8 to 4 bytes.

esphome/components/web_server_base/web_server_base.h

@@ -135,7 +135,7 @@ class WebServerBase {
   uint16_t get_port() const { return port_; }
 
  protected:
-  int initialized_{0};
+  uint8_t initialized_{0};
   uint16_t port_{80};
   AsyncWebServer *server_{nullptr};
   std::vector<AsyncWebHandler *> handlers_;