Enable toggling breakpoints in LSP CEditor

This is an example of where we have somewhat an inversion of dependencies.
The existing CDT code assumes it knows about all types of editors
at compile time. In this case the LSP C Editor is a new type. However,
rather than creating a new extension mechanism here we are simply
adding the LSP C Editor to the known list as the LSP C Editor
is (or will soon be) part of CDT itself anyway (see #354)

By itself this change doesn't do anything, it needs the
change in eclipse-cdt/cdt-lsp#46

Also-by: Gesa HENTSCHKE <Gesa.HENTSCHKE@bachmann.info>

debug/org.eclipse.cdt.debug.ui/src/org/eclipse/cdt/debug/internal/ui/breakpoints/ToggleCBreakpointTester.java

@@ -28,6 +28,7 @@
 import org.eclipse.cdt.internal.ui.editor.asm.AsmTextEditor;
 import org.eclipse.core.expressions.PropertyTester;
 import org.eclipse.core.resources.IResource;
+import org.eclipse.ui.editors.text.TextEditor;
 
 /**
  * Toggle breakpoint factor enablement tester for editors and IDeclaration.
@@ -117,6 +118,14 @@ public boolean test(Object receiver, String property, Object[] args, Object expe
 					}
 				}
 			}
+
+			// Test for LSP based C/C++ Editor
+		} else if ("isCEditorSupportsCBreakpoint".equals(property) && (receiver instanceof TextEditor)) { //$NON-NLS-1$
+			var editor = (TextEditor) receiver;
+			if (editor.getEditorSite() == null || !editor.getEditorSite().getId().equals("org.eclipse.cdt.lsp.CEditor")) //$NON-NLS-1$
+				return false;
+			if (!CDebugUtils.isCustomToggleBreakpointFactory())
+				return true;
 		}
 
 		return false;