HTTP Client Should Use Reqwest 0.13

### Describe the problem

I'm using the http client plugin and the updater plugin. That means my Cargo.lock file includes two different version of reqwest. It's probably also a good idea to inform the user in the [http client docs](https://v2.tauri.app/plugin/http-client/#rust) what features to specify when adding the plugin to my cargo.toml. Otherwise, you get the bug where `.json` happens to work 6 months ago only because the updater plugin included the same version of reqwest as the http client but with the json feature. So of course when I updated my cargo.lock file, my code does not compile since reqwest 0.12 was not included with the json feature!

### Describe the solution you'd like

1. Inform user in http client docs of the features available when adding to cargo.toml
2. Bump reqwest version to 0.13 to reduce dependencies when multiple tauri plugins are being used.

### Alternatives considered

_No response_

### Additional context

_No response_

Start with the HTTP client and updater plugin dependency declarations and compare their reqwest versions and enabled features in Cargo.toml and Cargo.lock. Review the Rust section of the HTTP client docs at the linked page for the feature guidance. Done means reqwest is aligned at 0.13, the available Cargo features are documented, and the affected plugins compile together.

Written by the indexing model from the issue text.