Bump sp-keyring from 7d3ce4d to 4987488

Bumps [sp-keyring](https://github.com/paritytech/polkadot-sdk) from `7d3ce4d` to `4987488`.
- [Release notes](https://github.com/paritytech/polkadot-sdk/releases)
- [Commits](paritytech/polkadot-sdk@7d3ce4d...4987488)

---
updated-dependencies:
- dependency-name: sp-keyring
  dependency-type: direct:production
...

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