feat(tauri): add plugin_boxed methods

[WSH032]

Describe the problem

Because this PR is small enough, I didn’t open a feature request issue in advance.

I am implementing the feature to add tauri plugins from Python for pytauri: pytauri/pytauri#220.
In pyo3/pytauri, we cannot use generics, so I store these TauriPlugin as Box<dyn Plugin>.

However, Box<dyn Plugin> itself does not implement the Plugin trait, so I cannot use them in Builder::plugin and AppHandle::plugin.

Describe the solution you'd like

Therefore, I would like to add plugin_dyn methods to accept Box<dyn Plugin> instead of impl Plugin<R>.

Alternatives considered

Alternatively, we could impl Plugin<R> for Box<dyn Plugin<R>>. But I don't really like this approach, because it would result in Box<Box<dyn Plugin<R>>>.

But if tauri doesn't want to add a new API, I can also accept this implementation.

[github-actions]

Package Changes Through 55faa2d

There are 7 changes which include @tauri-apps/cli with patch, tauri-cli with minor, @tauri-apps/api with minor, tauri-runtime-wry with patch, tauri-bundler with patch, tauri with minor, tauri-utils with minor

Planned Package Versions

The following package releases are the planned based on the context of changes in this pull request.

package	current	next
@tauri-apps/api	2.6.0	2.7.0
tauri-utils	2.5.0	2.6.0
tauri-bundler	2.5.0	2.5.1
tauri-runtime	2.7.0	2.7.1
tauri-runtime-wry	2.7.1	2.7.2
tauri-codegen	2.3.0	2.3.1
tauri-macros	2.3.1	2.3.2
tauri-plugin	2.3.0	2.3.1
tauri-build	2.3.0	2.3.1
tauri	2.6.2	2.7.0
@tauri-apps/cli	2.6.2	2.6.3
tauri-cli	2.6.2	2.7.0

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[Legend-Master]

Don't mind adding it personally

[Legend-Master]

Will wait for you to sign the commits when you get back 🙃