Remove duplicate rows.

variants/heltec_wireless_paper/platformio.ini

@@ -29,7 +29,6 @@ build_flags =
   -D WIRELESS_PAPER
 build_src_filter = ${esp32_base.build_src_filter}
   +<../variants/heltec_wireless_paper>    
-  +<helpers/ui/MomentaryButton.cpp>
 lib_deps =
   ${esp32_base.lib_deps}
   https://github.com/todd-herbert/heltec-eink-modules/archive/9207eb6ab2b96f66298e0488740218c17b006af7.zip