revealFileInOS may ignore the passed URI or pick additional URIs from Explorer selection depending on UI state

During extension development, an issue was encountered where `commands.executeCommand('revealFileInOS', uri)` may ignore the passed URI and use the current Explorer selection instead. For example: (1) an item is selected in the Explorer view, and (2) the command is invoked without switching to another view/editor, by using an extension tree view title context menu.

In general, the provided URI argument is ignored when the Explorer View is focused, has a selection, and the provided URI is not part of that selection.

According to discussions in issues such as #110869 and #232522, `revealFileInOS` appears to be an internal command tied to the Explorer view, and extensions may be expected to implement their own revealing approach.

However, the following code was found to use `revealFileInOS` with an explicit URI, relying on it to reveal the specified resource:

* https://github.com/microsoft/vscode/blob/main/extensions/copilot/src/extension/log/vscode-node/requestLogTree.ts
* https://github.com/microsoft/vscode/blob/main/extensions/typescript-language-features/src/typescriptServiceClient.ts
* https://github.com/microsoft/vscode/blob/main/extensions/git/src/commands.ts
* https://github.com/microsoft/vscode/blob/main/src/vs/workbench/contrib/chat/browser/agentPluginActions.ts
* https://github.com/microsoft/vscode/blob/main/src/vs/workbench/contrib/chat/browser/actions/chatPluginActions.ts
* https://github.com/microsoft/vscode/blob/main/src/vs/workbench/contrib/chat/browser/actions/createPluginAction.ts
* https://github.com/microsoft/vscode/blob/main/src/vs/workbench/contrib/chat/browser/aiCustomization/aiCustomizationManagement.contribution.ts

These consumers may reveal incorrect paths if an unrelated item is selected in the Explorer during execution.

It seems that one of the following approaches may be needed:

* Fix `revealFileInOS` (`getMultiSelectedResources`) so an explicitly passed URI is always respected, while preserving the existing multi-selection behavior where needed.
* Change the listed consumers to avoid `revealFileInOS` and instead use a revealing mechanism that operates directly on the specified URI.
* Introduce a separate command for revealing explicitly specified URIs that is independent of Explorer selection and view focus state, also accessible by extensions.