fix: fasta headers from sequence extractor output are truncated

[ninsch3000]

Where the fasta header from bedtools output is

>1:3069197-3069296(+)

the one from the subsequent step (adding poly(A) tails) is

>1:3069197-30692

Investigate module sequence extractor/post-bed processing to identify the cause for this behavior.

[ninsch3000]

Note to self: Tool is expecting the header to contain transcript ids, and is then only considering the first 15 characters. So header output from bedtools has to be changed, and then the transcript selection has to be revisited.