Hide some non-applicable settings for tree supports to prevent confusion (#12367)

Hide tree support parameters not in use

- hide independent support layer height for organic tree support
- hide threshold overlap for tree supports

Co-authored-by: SoftFever <softfeverever@gmail.com>

src/libslic3r/PrintConfig.cpp

@@ -6183,7 +6183,10 @@ void PrintConfigDef::init_fff_params()
     def = this->add("support_threshold_angle", coInt);
     def->label = L("Threshold angle");
     def->category = L("Support");
-    def->tooltip = L("Support will be generated for overhangs whose slope angle is below the threshold.");
+    def->tooltip = L("Support will be generated for overhangs whose slope angle is below the threshold. "
+                     "The smaller this value is, the steeper the overhang that can be printed without support.\n"
+                     "Note: If set to 0, normal supports use the Threshold overlap instead, "
+                     "while tree supports fall back to a default value of 30.");
     def->sidetext = u8"°";	// degrees, don't need translation
     def->min = 0;
     def->max = 90;