config: make sending the user agent configurable, disable sending the user agent in tests

config/config.exs

@@ -192,6 +192,7 @@
 # Configures http settings, upstream proxy etc.
 config :pleroma, :http,
   proxy_url: nil,
+  send_user_agent: true,
   adapter: [
     ssl_options: [
       # We don't support TLS v1.3 yet

config/test.exs

@@ -63,6 +63,8 @@
 
 config :pleroma, :http_security, report_uri: "https://endpoint.com"
 
+config :pleroma, :http, send_user_agent: false
+
 rum_enabled = System.get_env("RUM_ENABLED") == "true"
 config :pleroma, :database, rum_enabled: rum_enabled
 IO.puts("RUM enabled: #{rum_enabled}")

lib/pleroma/http/request_builder.ex

@@ -46,7 +46,13 @@ def url(request, u) do
   """
   @spec headers(map(), list(tuple)) :: map()
   def headers(request, header_list) do
-    header_list = header_list ++ [{"User-Agent", Pleroma.Application.user_agent()}]
+    header_list =
+      if Pleroma.Config.get([:http, :send_user_agent]) do
+        header_list ++ [{"User-Agent", Pleroma.Application.user_agent()}]
+      else
+        header_list
+      end
+
     Map.put_new(request, :headers, header_list)
   end