ProblemsView context menu only shows 'Collapse All'

[eneufeld]

Bug Description:

After the update to Theia 1.34 the problems view only shows one context entry: Collapse All

Furthermore the following stack trace is logged:

2023-03-02T11:59:52.043Z root ERROR TypeError: Cannot use 'in' operator to search for 'kind' in undefined
    at Object.is (http://localhost:3000/packages_markers_lib_browser_problem_problem-manager_js.js:296:23)
    at Object.is (http://localhost:3000/packages_markers_lib_browser_problem_problem-widget_js.js:409:78)
    at CommandHandler.toSelection (http://localhost:3000/packages_markers_lib_browser_problem_problem-widget_js.js:414:61)
    at CommandHandler.getSelection (http://localhost:3000/packages_filesystem_lib_browser_breadcrumbs_filepath-breadcrumb_js-packages_filesystem_lib_br-eff824.js:50:52)
    at CommandHandler.isVisible (http://localhost:3000/packages_filesystem_lib_browser_breadcrumbs_filepath-breadcrumb_js-packages_filesystem_lib_br-eff824.js:39:32)
    at CommandRegistry.getVisibleHandler (http://localhost:3000/bundle.js:139171:55)
    at CommandRegistry.isVisible (http://localhost:3000/bundle.js:139133:28)
    at MenuCommandExecutorImpl.delegate (http://localhost:3000/bundle.js:142270:43)
    at MenuCommandExecutorImpl.isVisible (http://localhost:3000/bundle.js:142258:21)
    at SampleMenuCommandRegistry.registerCommand (http://localhost:3000/packages_core_lib_browser_menu_browser-menu-plugin_js.js:435:41)

The reason for this is most likely this change: 83b726e#diff-af21beb4f671b6cf6cd72962b340942cd675026547f91ccc93c4e96b732fb2c5R28

The problem-selection.ts does not check anymore that a marker property exists. The problem-marker.ts needs to have an isObject check.

Steps to Reproduce:

1. Create a file that produces an error, eg a javascript file with:

const a = () {
    let b = 'x';
};

2. Open the problems view
3. right click on any entry
4. By default there should be 3 entries: Copy, Copy Message and Collapse All

Additional Information

• Operating System: Linux
• Theia Version: 1.34 tested on commit f7ef6b56471926d30809e56de946fe61dddefb64