Passing state to tool so that we can use them in custom tools

[Jrakru]

Allows the use of $flow.state.var inside the custom tool by passing the state in the ToolNode:

for example:

we have the output

when we use the following function in the custom tool node: return successfully called tool ${$flow.state.test}`;

This is inlie with the behaviour mentionsed in the How to Use Function

Previously we were getting the following an error:

Ps: I am only passing the state without the messages since we are already using the toolNode to get the functions to calls. I dont see why we would need the messages in the tool itself but I could be shortsighted on this.

[HenryHengZJ]

think we can close this one since this PR (#3075) is merged and it fixed the issue

[HenryHengZJ]

thank you so much @Jrakru !