Remove outdated translation of STR_6437, STR_6438

[Wuzzy2]

This removes the (outdated) translations of STR_6437 and STR_6438. I do this because the meaning of these strings changed to the opposite (invisible to visible), so this is pretty nasty to still have the old (and VERY wrong translations. I therefore remove them in this PR.

See also: #2264

[github-actions]

Check results

For details go to Translation Check -> Details. Expand Run checks build stage and use the build-in search to find your language (e.g. pl-PL)

	Missing The translation is not added to translation file. (e.g. STR_9999 is in en-GB but is not available in given language)	Not needed The translation file contains entries that are not in en-GB and should be removed (e.g. STR_9999 exits in given language but is not in en-GB)	Same The translation and source string is exactly the same. (e.g. STR_9999 is Umbrella in both en-GB and given language). This may be desired in some cases (e.g. April is the same in English and German)
da-DK	2 (+2)	4	484
de-DE	2 (+2)	4	328
fi-FI	5 (+2)	4	107
hu-HU	218 (+2)	4	89
zh-TW	32 (+2)	4	330

Other translations

	Missing The translation is not added to translation file. (e.g. STR_9999 is in en-GB but is not available in given language)	Not needed The translation file contains entries that are not in en-GB and should be removed (e.g. STR_9999 exits in given language but is not in en-GB)	Same The translation and source string is exactly the same. (e.g. STR_9999 is Umbrella in both en-GB and given language). This may be desired in some cases (e.g. April is the same in English and German)
ar-EG	331	3	2133
ca-ES	82	4	100
cs-CZ	352	4	233
en-US	3289	0	390
eo-ZZ	0	4	83
es-ES	0	0	289
fr-FR	0	4	148
it-IT	19	4	305
ja-JP	105	11	659
ko-KR	0	4	171
nb-NO	325	3	2225
nl-NL	0	16	413
pl-PL	0	0	398
pt-BR	0	4	131
ru-RU	1393	1	110
sv-SE	0	0	340
tr-TR	187	10	396
vi-VN	26	6	3381
zh-CN	177	3	454

[Gymnasiast]

Two of these languages got an update by their translators in the meantime (de and zh-TW) and the remaining three have been updated here: 5310e37

With that, the old "invisible" translation is now gone from all languages.