fix: generate-key-using-seed-phrase

[hanakannzashi]

fix issue #949

• The wrong keyStore variable was used before, resulting in two key pair files generated when using near generate-key --seedPhrase="xxx"

[think-in-universe]

The fix make sense to me. @volovyks

[volovyks]

Thank you @hanakannzashi ! It would be great to add a simple test for this change.
And in general, we need to turn on tests from external contributors in this repo. cc @ailisp I think it should be a standard for all repos where we expect contributions, I suppose, all tooling repos.

Related issue: near/near-workspaces-js#200
For some reason I was not able to turn this feature on there.

[hanakannzashi]

Thank you @hanakannzashi ! It would be great to add a simple test for this change. And in general, we need to turn on tests from external contributors in this repo. cc @ailisp I think it should be a standard for all repos where we expect contributions, I suppose, all tooling repos.

Related issue: near/workspaces-js#200 For some reason I was not able to turn this feature on there.

This PR still has some issue, I will close it later. I am not particularly clear about the purpose of MergeKeyStore in this project. The code of generate-key.js is very strange, I think there are many issues in this file. Also, I can't unstand the code on seed-phrase.js