Implement missing Integration Manager API actions

### Your use case

#### What would you like to do?
Add support for these missing Integration Manager postmessage API actions in order to have parity with `matrix-react-sdk`:

* `get_open_id_token`
* [Description](https://github.com/matrix-org/matrix-react-sdk/blob/432ce3ca31a830faf3887c6fb3859dc47caaf55d/src/ScalarMessaging.ts#L261-L266)
* [Reference implementation](https://github.com/matrix-org/matrix-react-sdk/blob/432ce3ca31a830faf3887c6fb3859dc47caaf55d/src/ScalarMessaging.ts#L714)
* `kick`
* [Description](https://github.com/matrix-org/matrix-react-sdk/blob/432ce3ca31a830faf3887c6fb3859dc47caaf55d/src/ScalarMessaging.ts#L76-L97)
* [Reference implementation](https://github.com/matrix-org/matrix-react-sdk/blob/432ce3ca31a830faf3887c6fb3859dc47caaf55d/src/ScalarMessaging.ts#L381)
* `send_event`
* [Description](https://github.com/matrix-org/matrix-react-sdk/blob/432ce3ca31a830faf3887c6fb3859dc47caaf55d/src/ScalarMessaging.ts#L268-L279)
* [Reference implementation](https://github.com/matrix-org/matrix-react-sdk/blob/432ce3ca31a830faf3887c6fb3859dc47caaf55d/src/ScalarMessaging.ts#L724)
* `read_events`
* [Description](https://github.com/matrix-org/matrix-react-sdk/blob/432ce3ca31a830faf3887c6fb3859dc47caaf55d/src/ScalarMessaging.ts#L281-L290)
* [Reference implementation](https://github.com/matrix-org/matrix-react-sdk/blob/432ce3ca31a830faf3887c6fb3859dc47caaf55d/src/ScalarMessaging.ts#L782)

#### Why would you like to do it?
In order to support new integration manager functionality.

#### How would you like to achieve it?
Add these actions to the existing Integration Manager postmessage API implementation: https://github.com/vector-im/element-ios/blob/4933a56285c742951d5c7a987cccb8aff8820dd1/Riot/Modules/Integrations/IntegrationManagerViewController.m#L165-L167

### Have you considered any alternatives?

_No response_

### Additional context

_No response_

Start at the existing Integration Manager postmessage API implementation in Riot/Modules/Integrations/IntegrationManagerViewController.m around lines 165-167. Compare the four requested actions with the referenced ScalarMessaging.ts descriptions and implementations in matrix-react-sdk. Done means the iOS implementation supports get_open_id_token, kick, send_event, and read_events for integration manager functionality.

Written by the indexing model from the issue text.