feat(Blocks): Add For-Each Block for iterating over a List. (#7531)

* feat: Add ForEachBlock for iterating over a List.

---------

Co-authored-by: Swifty <craigswift13@gmail.com>

rnd/autogpt_server/autogpt_server/blocks/foreach_block.py

@@ -0,0 +1,35 @@
+from typing import Any, List, Tuple
+
+from autogpt_server.data.block import Block, BlockOutput, BlockSchema
+from autogpt_server.data.model import SchemaField
+
+
+class ForEachBlock(Block):
+    class Input(BlockSchema):
+        items: List[Any] = SchemaField(
+            description="The list of items to iterate over",
+            placeholder="[1, 2, 3, 4, 5]",
+        )
+
+    class Output(BlockSchema):
+        item: Tuple[int, Any] = SchemaField(
+            description="A tuple with the index and current item in the iteration"
+        )
+
+    def __init__(self):
+        super().__init__(
+            id="f8e7d6c5-b4a3-2c1d-0e9f-8g7h6i5j4k3l",
+            input_schema=ForEachBlock.Input,
+            output_schema=ForEachBlock.Output,
+            test_input={"items": [1, "two", {"three": 3}, [4, 5]]},
+            test_output=[
+                ("item", (0, 1)),
+                ("item", (1, "two")),
+                ("item", (2, {"three": 3})),
+                ("item", (3, [4, 5])),
+            ],
+        )
+
+    def run(self, input_data: Input) -> BlockOutput:
+        for index, item in enumerate(input_data.items):
+            yield "item", (index, item)