fix(examples): prevent conflict between recently viewed items and searches plugins

[dhayab]

Summary

CR-4071 has found an issue with autocomplete when a customer adds both the recent searches plugin and the userland recently viewed items plugin we provide as an example. This is because the last is based on the first, and both share the same plugin name and source id.

This PR makes sure the userland code we provide for the recently viewed items plugin sets its own source id and plugin name.

[codesandbox-ci]

This pull request is automatically built and testable in CodeSandbox.

To see build info of the built libraries, click here or the icon next to each commit SHA.

Latest deployment of this branch, based on commit 0c72dd7:

Sandbox	Source
@algolia/autocomplete-example-github-repositories-custom-plugin	Configuration
@algolia/autocomplete-example-instantsearch	Configuration
@algolia/autocomplete-example-playground	Configuration
@algolia/autocomplete-example-preview-panel-in-modal	Configuration
@algolia/autocomplete-example-react-renderer	Configuration
@algolia/autocomplete-example-starter-algolia	Configuration
@algolia/autocomplete-example-starter	Configuration
@algolia/autocomplete-example-reshape	Configuration
@algolia/autocomplete-example-vue	Configuration

[Haroenv]

🅰️h, I didn't realise that the source id would have this effect

[Haroenv]

I meant to approve