Fix missing multisig signatures

[bobanm]

What was the problem?

This PR resolves #9094

How was it solved?

Changed transaction:sign command to no longer hardcode private key derivation to legacy method. Now it uses deriveKeypair() function which will use either legacy or key path derivation, depending on the provided --key-derivation-path flags.

How was it tested?

When signing a multisig transactions offline, every signing from a different multisig signer now adds an additional signature to transaction's signatures array.

[codecov]

Codecov Report

Merging #9095 (0097fc5) into release/6.0.0 (c9c1ecc) will increase coverage by 0.04%.
Report is 14 commits behind head on release/6.0.0.
The diff coverage is 96.81%.

@@                Coverage Diff                @@
##           release/6.0.0    #9095      +/-   ##
=================================================
+ Coverage          83.47%   83.51%   +0.04%     
=================================================
  Files                604      606       +2     
  Lines              22803    22828      +25     
  Branches            3364     3365       +1     
=================================================
+ Hits               19035    19065      +30     
+ Misses              3768     3763       -5     

Files	Coverage Δ
...der/src/bootstrapping/commands/transaction/sign.ts	93.05% <100.00%> (+0.95%)	⬆️
commander/test/helpers/account.ts	31.03% <100.00%> (+2.46%)	⬆️
elements/lisk-chain/src/block_header.ts	73.13% <100.00%> (ø)
...ain-connector-plugin/src/certificate_generation.ts	97.95% <100.00%> (+0.04%)	⬆️
...ork-monitor-plugin/src/controllers/transactions.ts	22.22% <ø> (ø)
framework/src/engine/bft/method.ts	88.97% <100.00%> (+0.08%)	⬆️
...ne/consensus/certificate_generation/commit_list.ts	100.00% <100.00%> (ø)
framework/src/genesis_block.ts	86.95% <ø> (ø)
...nteroperability/base_cross_chain_update_command.ts	97.71% <100.00%> (+0.06%)	⬆️
...rability/base_interoperability_internal_methods.ts	94.13% <100.00%> (+1.20%)	⬆️
... and 20 more

... and 3 files with indirect coverage changes

[shuse2]

LGTM, as we discussed, it would be good to add a test for the default key derivation as well for checking integration