idl: Support PDA resolution of call expressions that don't have any arguments

[acheroncrypto]

Problem

Call expressions that have no arguments do not get resolved automatically. For example:

#[derive(Accounts)]
pub struct CallExprWithNoArgs<'info> {
    #[account(
        seeds = [System::id().as_ref()],
        seeds::program = System::id(),
        bump
    )]
    pub pda: UncheckedAccount<'info>,
}

This generates the following account (with no resolution information):

{ "name": "pda" }

However, we have all the necessary information to evaluate the key of pda during IDL build (because System::id() can be evaluated).

Summary of changes

Support PDA resolution of call expressions that don't have any arguments.

[vercel]

@acheroncrypto is attempting to deploy a commit to the coral-xyz Team on Vercel.

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