fix[resample/main]: .flac rebuild block type check breaks as fr.block_type is not bytes

[samicrusader]

When going through some .flac releases with retag, I encountered an error with resample:

D:\!move\srrGUI>retag.py ".\_srr\_done\Fatboy_Slim-The_Rockafeller_Skank-CDM-FLAC-1998-c05_INT.srr" -y -i ".\_in\flac\Fatboy_Slim-The_Rockafeller_Skank-CDM-FLAC-1998-c05_INT" -o ".\_out\FLAC\Fatboy_Slim-The_Rockafeller_Skank-CDM-FLAC-1998-c05_INT"
Extracting 00-fatboy_slim-the_rockafeller_skank-cdm-flac-1998.nfo
Extracting 00-fatboy_slim-the_rockafeller_skank-cdm-flac-1998-proof.jpg
Extracting 00-fatboy_slim-the_rockafeller_skank-cdm-flac-1998.m3u
Extracting 00-fatboy_slim-the_rockafeller_skank-cdm-flac-1998.sfv
Using 01-fatboy_slim-the_rockafeller_skank_(short_edit).srs
Fixing 01-fatboy_slim-the_rockafeller_skank_(short_edit).flac
From .\_in\flac\Fatboy_Slim-The_Rockafeller_Skank-CDM-FLAC-1998-c05_INT\01-fatboy_slim-the_rockafeller_skank_(short_edit).flac
SRS Load Complete...          Elapsed Time: 0.00s
Track Location Complete...    Elapsed Time: 0.00s
Track Extraction Complete...  Elapsed Time: 0.04s
Traceback (most recent call last):
  File "C:\Program Files\Python313\Lib\site-packages\resample\srs.py", line 514, in main
    sfile = sample.rebuild_sample(srs_data, tracks, attachments,
                                                          srs, out_file)
  File "C:\Program Files\Python313\Lib\site-packages\resample\main.py", line 668, in rebuild_sample
    return flac_rebuild_sample(self, *args, **kwargs)
  File "C:\Program Files\Python313\Lib\site-packages\resample\main.py", line 3772, in flac_rebuild_sample
    elif (fr.block_type in bytearray(b"stu") and
          ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^
TypeError: a bytes-like object is required, not 'str'
Unexpected Error:
a bytes-like object is required, not 'str'

fr.block_type as in resample/flac.py is usually a int as it's just unpacked from it's byte form; but is also str when dealing with the flac header "fLaC"; but files improperly tagged with ID3 tagging has block types "ID3" and "TAG".

Strings can't be compared to bytes in a bytearray; instead check against the ordinal values of "s", "t" and "u", which can be compared against bytes, strings and integers. This allows the release to be rebuilt.

The release used, Fatboy_Slim-The_Rockafeller_Skank-CDM-FLAC-1998-c05_INT, uses ID3 tagging which introduces block_types "ID3" and "TAG". The "fLaC" type is checked against explicitly; the error I'm seeing is after the flac header check fails over into the elif.
Adding a print(fr.block_type, type(fr.block_type)) to the fr.read() while loop shows this:

Using 04-fatboy_slim-tweakers_delight.srs
Fixing 04-fatboy_slim-tweakers_delight.flac
From .\_in\flac\Fatboy_Slim-The_Rockafeller_Skank-CDM-FLAC-1998-c05_INT\04-fatboy_slim-tweakers_delight.flac
SRS Load Complete...          Elapsed Time: 0.00s
Track Location Complete...    Elapsed Time: 0.00s
Track Extraction Complete...  Elapsed Time: 0.03s
ID3 <class 'str'>
fLaC <class 'str'>
115 <class 'int'>
116 <class 'int'>
117 <class 'int'>
0 <class 'int'>
3 <class 'int'>
4 <class 'int'>
129 <class 'int'>
TAG <class 'str'>

-= Links for testing =-
The SRR used: https://www.srrdb.com/download/srr/Fatboy_Slim-The_Rockafeller_Skank-CDM-FLAC-1998-c05_INT
The release itself: https://tanizaki.angelicdust.net/Fatboy_Slim-The_Rockafeller_Skank-CDM-FLAC-1998-c05_INT.zip

[samicrusader]

This will probably fix #23.