Fix #79294: ::columnType() may fail after SQLite3Stmt::reset()

The fix for feature request #53466 did not properly handle resetting of
the corresponding statement; the problem with this is that the
statement does not know about its result sets.  But even if we could
fix this, the `complete` handling still appears to be brittle, since
the `sqlite3_column_type()`docs[1] state:

| If the SQL statement does not currently point to a valid row, or if
| the column index is out of range, the result is undefined.

Fortunately, we can use `sqlite3_data_count()` instead, since[2]:

| If prepared statement P does not have results ready to return (via
| calls to the sqlite3_column() family of interfaces) then
| sqlite3_data_count(P) returns 0.

Thus, we guard `SQLite3::columnType()` with `sqlite3_data_count()`, and
completely drop updating the `php_sqlite3_result_object.complete`
field, but keep it for ABI BC purposes.

[1] <https://www.sqlite.org/c3ref/column_blob.html>
[2] <https://www.sqlite.org/c3ref/data_count.html>

ext/sqlite3/php_sqlite3_structs.h

@@ -108,7 +108,7 @@ struct _php_sqlite3_result_object  {
 	zval stmt_obj_zval;
 
 	int is_prepared_statement;
-	int complete;
+	int complete; // unused
 	zend_object zo;
 };