[PyCharm Tables] PY-75205 Correctly parse column names in wide tables #PY-75205 Fixed

* Resolved an issue where column names were incorrectly parsed due to trimming in wide tables.
* Removed the previous fallback mechanism that issued an extra request to the Python backend for the wide tables' case as:
    * 1 additional request was insufficient for handling all wide table cases
    * It also introduced significant performance overhead, as an additional request was sent for every wide table after each cell execution.
* Currently, we provide columns names' completion for wide tables only for the subset of columns returned by get_frame.

GitOrigin-RevId: 12f7127068c5b56f1b82b26c95b10cf7461d77c7

python/pydevSrc/src/com/jetbrains/python/debugger/values/DataFrameDebugValueUtil.kt

@@ -75,11 +75,10 @@ private fun getDataWithColumnsNames(value: String): String? {
     !inSingleQuotes && !inDoubleQuotes && char == ']'
   }
 
-  return if (index != -1) {
-    value.substring(0, index + 1)
-  }
-  else {
-    null
+  return when {
+    index != -1 -> value.substring(0, index + 1)
+    value.endsWith("...") -> value.substring(0, value.length - 3)
+    else -> null
   }
 }