[xy] Fix list index out of range for dynamic blocks.

[wangxiaoyou1993]

Description

Fix list index out of range for dynamic blocks.

When setting both regular block and dynamic block as upstream blocks, dynamic child block throws the "list index out of range" error upon execution

Error

Traceback (most recent call last):

  File "/usr/local/lib/python3.10/site-packages/mage_ai/shared/retry.py", line 38, in retry_func

    return func(*args, **kwargs)

  File "/usr/local/lib/python3.10/site-packages/mage_ai/data_preparation/executors/block_executor.py", line 588, in __execute_with_retry

    return self._execute(

  File "/usr/local/lib/python3.10/site-packages/mage_ai/data_preparation/executors/block_executor.py", line 1077, in _execute

    result = self.block.execute_sync(

  File "/usr/local/lib/python3.10/site-packages/mage_ai/data_preparation/models/block/__init__.py", line 1315, in execute_sync

    raise err

  File "/usr/local/lib/python3.10/site-packages/mage_ai/data_preparation/models/block/__init__.py", line 1224, in execute_sync

    output = self.execute_block(

  File "/usr/local/lib/python3.10/site-packages/mage_ai/data_preparation/models/block/__init__.py", line 1512, in execute_block

    self.__get_outputs_from_input_vars(

  File "/usr/local/lib/python3.10/site-packages/mage_ai/data_preparation/models/block/__init__.py", line 1454, in __get_outputs_from_input_vars

    input_vars, kwargs_vars, upstream_block_uuids = self.fetch_input_variables(

  File "/usr/local/lib/python3.10/site-packages/mage_ai/data_preparation/models/block/__init__.py", line 1812, in fetch_input_variables

    return fetch_input_variables_for_dynamic_upstream_blocks(

  File "/usr/local/lib/python3.10/site-packages/mage_ai/data_preparation/models/block/dynamic/variables.py", line 527, in fetch_input_variables_for_dynamic_upstream_blocks

    kwargs_vars.append(kr[0])

IndexError: list index out of range

How Has This Been Tested?

• Tested with the dynamic blocks. It succeeded

Checklist

• The PR is tagged with proper labels (bug, enhancement, feature, documentation)
• I have performed a self-review of my own code
• I have added unit tests that prove my fix is effective or that my feature works
• I have commented my code, particularly in hard-to-understand areas
• I have made corresponding changes to the documentation
• If new documentation has been added, relative paths have been added to the appropriate section of docs/mint.json

cc: