Follow-up the PR #4335 (Debug char, fix compile errors for lcd pins)

[ghost]

Follow-up the PR #4335 (Debug char, fix compile errors for lcd pins)

It solves a flickering when SD card is inserted or removed at using a ASCII LCD + language_kana.h.
This fix is by @thinkyhead and [@Blue-Marlin](This need the same correction for MAPPER_NON as lcd_strlen%28%29) and @AnHardt, thus I much thankful to you again.

...Or, does alternative solution for fix available? Because

Probably not the best or real solution:

.
If it's true, please close this PR.

[AnHardt]

DE is a screen symbol at its own here.
We are pointing directly into the map of symbols.
No combining of the accent and the according character can be made.

-    if ((s[i] & 0xC0u) != 0x80u) j++;
 +    #if ENABLED(MAPPER_NON)
 +        j++;
 +    #else
 +      if ((s[i] & 0xC0u) != 0x80u) j++;
 +    #endif

should be more correct.

[ghost]

Thanks for the advice, I've updated.
And I've confirmed just now that it hasn't side effect in case of
ASCII LCD + language_kana.h,
ASCII LCD + language_en.h,
ASCII LCD + language_de.h,
GLCD + language_kana_utf8.h,
GLCD + language_en.h,
GLCD + language_de.h.

[thinkyhead]

Ah, I see the "non-printing 0xDE" character I was concerned about is shown as a printed character, so the code can be just as you have it here. Ok, then, good on us!