[refactor] #4277: Infallible key pair generation

[Arjentix]

Linked issue

• Closes [suggestion] Make key pair generation infallible #4277

Benefits

Less useless error-handling

Checklist

• I've read CONTRIBUTING.md
• I've used the standard signed-off commit format (or will squash just before merging)
• All applicable CI checks pass (or I promised to make them pass later)
• (optional) I've written unit tests for the code changes
• I replied to all comments after code review, marking all implemented changes with thumbs up

[coveralls]

Pull Request Test Coverage Report for Build 7917722012

Details

• -4 of 102 (96.08%) changed or added relevant lines in 17 files are covered.
• 1258 unchanged lines in 22 files lost coverage.
• Overall coverage decreased (-0.05%) to 56.74%

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Changes Missing Coverage	Covered Lines	Changed/Added Lines	%
cli/src/samples.rs	0	1	0.0%
tools/kagami/src/genesis.rs	0	1	0.0%
core/test_network/src/lib.rs	0	2	0.0%

Files with Coverage Reduction	New Missed Lines	%
core/src/query/store.rs	1	73.2%
core/src/smartcontracts/isi/mod.rs	8	76.49%
data_model/src/predicate.rs	9	86.8%
core/src/smartcontracts/isi/tx.rs	13	66.67%
crypto/src/kex/x25519.rs	14	66.1%
smart_contract/executor/derive/src/default.rs	15	0.0%
p2p/src/peer.rs	16	0.0%
core/src/wsv.rs	17	52.2%
core/src/queue.rs	18	93.52%
core/src/tx.rs	26	53.18%

Totals
Change from base Build 7884695009:	-0.05%
Covered Lines:	22741
Relevant Lines:	40079

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💛 - Coveralls