Remove '-' from list of allowed symbols in unaligned sequences.

[anna-parker]

resolves #

preview URL: https://no-gaps-in-unaligned.loculus.org/

Summary

'-' only makes sense in the context of aligned sequences. It is not accepted by ENA and is not included in official IUPAC lists: https://genome.ucsc.edu/goldenPath/help/iupac.html#:~:text=The%20International%20Union%20of%20Pure,for%20either%20G%20or%20A).

[fengelniederhammer]

I think the backend has the same problem:

loculus/backend/src/main/kotlin/org/loculus/backend/service/submission/ProcessedSequenceEntryValidator.kt

Lines 58 to 75 in 4df831f

	enum class NucleotideSymbols(override val symbol: Char) : Symbol {
	A('A'),
	C('C'),
	G('G'),
	T('T'),
	M('M'),
	R('R'),
	W('W'),
	S('S'),
	Y('Y'),
	K('K'),
	V('V'),
	H('H'),
	D('D'),
	B('B'),
	N('N'),
	GAP('-'),
	}

[anna-parker]

@fengelniederhammer the backend uses the nucleotide symbol list in the type check: validateNoUnknownNucleotideSymbol which is used for both unaligned and aligned sequences - it is a correct symbol for aligned sequences so I think it is ok to keep the backend as is.

[fengelniederhammer]

Isn't it the same issue? In aligned sequences - should be allowed, in unaligned it is not allowed. We could easily also introduce a new list in the backend that splits the validation.