🚑️ Bump frame-executive and sp-api-proc-macro (#492)

This PR updates dependencies in `Cargo.toml` and makes runtime changes in `runtimes/polimec/src/lib.rs`. The updates primarily include version bumps for various Polkadot-SDK dependencies.

### Dependency Updates in `Cargo.toml`:

* Updated versions for Substrate-related crates, including `xcm-emulator`, `frame-benchmarking`, `frame-executive`, `sp-npos-elections`, `pallet-scheduler`, `pallet-xcm`, and `sp-api-proc-macro`.

* Updated runtime versions for `westend-runtime`, `asset-hub-westend-runtime`, and `emulated-integration-tests-common`.

### Runtime Changes in `runtimes/polimec/src/lib.rs`:

* Simplified the `migrations` module by removing already executed migration, such as `RemovePallet`, and other legacy migration logic. 

* Incremented the `spec_version` from `1_001_000` to `1_001_001` and the `transaction_version` from `8` to `9`.

Author: lrazovic