Setting Hit Count for a breakpoint sometimes sets Expression instead

[pisv]

Steps to Reproduce:

1. Using Theia Electron (or Browser) Example on the master branch,
   add a source breakpoint in a JavaScript (or TypeScript) file.

2. Edit the breakpoint and set a Hit Count.

3. Edit the breakpoint again and remove the Hit Count.

4. Edit the breakpoint once again and set a Hit Count.

5. Note that the breakpoint has an Expression set to the value entered for the Hit Count (which can be seen in a tooltip for the breakpoint, and also in a debugger).

Observed	Expected

[pisv]

The source of the issue is that at step 4 the value initially selected in the select component of the DebugBreakpointWidget ('hitCondition') does not match the value of this.context ('condition').

It looks like the code in the DebugBreakpointWidget.render method attempts to synchronize the selection with the context using the defaultValue property of the SelectComponent:

theia/packages/debug/src/browser/editor/debug-breakpoint-widget.tsx

Lines 218 to 230 in c1a2b7b

	protected render(): void {
	if (this._input) {
	this._input.getControl().setValue(this._values[this.context] || '');
	}
	this.selectNodeRoot.render(<SelectComponent
	defaultValue={this.context} onChange={this.updateInput}
	options={[
	{ value: 'condition', label: nls.localizeByDefault('Expression') },
	{ value: 'hitCondition', label: nls.localizeByDefault('Hit Count') },
	{ value: 'logMessage', label: nls.localizeByDefault('Log Message') },
	]}
	/>);
	}

However, this property sets the selection at construction time only; it has no effect when the component is re-rendered.

I'll try to provide a patch.