chore(statemanager): enable `strict-boolean-expressions` rule for `eslint`

[faustbrian]

Part of https://github.com/ethereumjs/ethereumjs-monorepo/issues/2137

[codecov[bot]]

Codecov Report

Merging #2152 (3a1da02) into master (f5a1d77) will decrease coverage by 7.04%. The diff coverage is 61.66%.

Flag	Coverage Δ
block	83.81% <100.00%> (?)
blockchain	80.46% <50.00%> (?)
client	77.06% <ø> (?)
common	95.31% <66.66%> (?)
devp2p	82.44% <ø> (?)
ethash	90.81% <42.85%> (?)
evm	40.71% <ø> (?)
rlp	90.47% <0.00%> (ø)
statemanager	84.61% <87.50%> (?)
trie	81.49% <100.00%> (?)
util	87.22% <ø> (?)
vm	?

Flags with carried forward coverage won't be shown. Click here to find out more.

[faustbrian]

Closing this since it falls in the same category as Uint8Array in terms of breaking changes/impact.