fix: fixed namespaceID parsing from toml

[mtsitrin]

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[codecov]

Codecov Report

Merging #373 (081c3c5) into main (1a683ca) will decrease coverage by 0.11%.
The diff coverage is 38.88%.

@@            Coverage Diff             @@
##             main     #373      +/-   ##
==========================================
- Coverage   52.25%   52.14%   -0.11%     
==========================================
  Files          89       90       +1     
  Lines       14197    14216      +19     
==========================================
- Hits         7418     7413       -5     
- Misses       5745     5761      +16     
- Partials     1034     1042       +8     

Impacted Files	Coverage Δ
da/celestia/celestia.go	64.92% <20.00%> (-2.07%)	⬇️
da/celestia/config.go	62.50% <62.50%> (ø)

... and 5 files with indirect coverage changes

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[omritoptix]

don't really like the duplication here. if I understand correctly the goal is to parse namespace id from string to bytes. I believe previously it has been done in the config file.
why do you think using AuxConfig is preferred?
Another option is possibly to add a field to the main config.
Creating 2 config which are basically the same but one field seems very confusing to me.

[mtsitrin]

Yeah I'll figure out better way