Replace illustration for add contact nearby error

briar-android/artwork/il_qr_code_error_dark.svg

briar-android/artwork/il_qr_code_error_light.svg

briar-android/artwork/qr_code_error.svg

...oid/contact/add/nearby/AddNearbyContactErrorFragment.java

...-android/src/main/res/drawable-night/il_qr_code_error.xml

briar-android/src/main/res/drawable/il_qr_code_error.xml

briar-android/src/main/res/drawable/qr_code_error.xml

...d/src/main/res/layout/fragment_error_contact_exchange.xml

briar-android/src/main/res/values/strings.xml