Bumps [fast-uri](https://github.com/fastify/fast-uri) from 3.1.8 to 3.1.9.
- [Release notes](https://github.com/fastify/fast-uri/releases)
- [Commits](https://github.com/fastify/fast-uri/compare/v3.1.8...v3.1.9)

---
updated-dependencies:
- dependency-name: fast-uri
  dependency-version: 3.1.9
  dependency-type: indirect
...

Signed-off-by: dependabot[bot] <support@github.com>

An online key registration transaction with voteFirst=0 (a legitimate
round value) failed to encode: the field was dropped during msgpack
serialization because OptionalSchema treats the wrapped schema's default
(0 for Uint64Schema) as an omit-empty default. On decode the field was
restored as undefined, so reconstructing the Transaction threw "Online
key registration missing at least one of the following fields: voteKey,
selectionKey, voteFirst, voteLast, voteKeyDilution". The same error
occurred when decoding a block containing such a transaction.

Introduce SparseOptionalSchema, which treats only `undefined` (not the
wrapped schema's zero default) as omittable, and use it for the votefst,
votelst and votekd fields. These fields remain omittable so they stay
absent on non-keyreg transactions, leaving other transaction types' wire
format unchanged.

Fixes #925