Align getRandomSeed() implementation to protocol changes from LIP-46

[bobanm]

What was the problem?

This PR resolves #8154. It is related only to the second point about changes in PR related to getRandomBytes() and getRandomSeed(). The remaining points from this original issue have been tracked by the newly created, isolated issues, because they need to be merged into different branches.

How was it solved?

• updated getRandomSeed() function, as per the LIP change
• removed redundant import of lisk-cryptography package
• updated unit tests for getRandomSeed()
• removed redundant import of protocol spec fixture from the test suite
• removed duplicated symlink to protocol spec fixture
• updated protocol spec fixture generator with the new logic
• re-generated protocol spec fixtures using the updated generator

How was it tested?

Run the updated test suite, and all tests are passing 👌🏻

[codecov]

Codecov Report

Merging #8570 (546106b) into release/6.0.0 (fe67ea1) will decrease coverage by 0.01%.
The diff coverage is 100.00%.

Additional details and impacted files

@@                Coverage Diff                @@
##           release/6.0.0    #8570      +/-   ##
=================================================
- Coverage          83.31%   83.31%   -0.01%     
=================================================
  Files                593      593              
  Lines              22300    22297       -3     
  Branches            3279     3278       -1     
=================================================
- Hits               18579    18576       -3     
  Misses              3721     3721              

Impacted Files	Coverage Δ
framework/src/modules/random/utils.ts	96.42% <100.00%> (-0.19%)	⬇️

[gkoumout]

Looks good to me, just left some small comments.

I am not able to judge the changes related to the lisk-cryptography package and files of folder generator_outputs/dpos_random_seed_generation, so I assume this will be reviewed within SDK.