patch 8.2.3624: when renaming a terminal buffer status text is not updated

Problem:    When renaming a terminal buffer the status text is not updated.
Solution:   Clear the cached status text when renaming a terminal buffer.
            (closes #9162)

src/terminal.c

@@ -4637,6 +4637,15 @@ term_get_status_text(term_T *term)
     return term->tl_status_text;
 }
 
+/*
+ * Clear the cached value of the status text.
+ */
+    void
+term_clear_status_text(term_T *term)
+{
+    VIM_CLEAR(term->tl_status_text);
+}
+
 /*
  * Mark references in jobs of terminals.
  */