Check category and country in "Import series from an external site" test case

[php-coder]

We should resolve the following TODOs:

mystamps/src/test/robotframework/series/import/request-logic.robot

Lines 24 to 27 in 29f6dc9

	${encodedUrl}= Encode URL http://127.0.0.1:8080/image/1
	Location Should Be ${SITE_URL}/series/add?category=prehistoric-animals&country=italy&image_url=${encodedUrl}
	# TODO: verify category
	# TODO: verify country

and

mystamps/src/test/robotframework/series/import/request-logic.robot

Lines 45 to 48 in 29f6dc9

	${encodedUrl}= Encode URL http://localhost:8080/image/1
	Location Should Be ${SITE_URL}/series/add?category=prehistoric-animals&country=italy&image_url=${encodedUrl}
	# TODO: verify category
	# TODO: verify country

Tech debt for 29f6dc9 (#660)

[php-coder]

Country check were added in 97e27e3 during import redesign (see #709).