Remove @Sendable and @escaping restrictions from condition(:_), timeout(for:body:) and withCancellationShield(_:)

[bauer-andreas]

Motivation

Currently, the methods condition(:_), timeout(for:body:) and withCancellationShield(_:) require the closure they accept to be @escaping or @Sendable/sending. None of these requirements are actually true.
The closure getting passed to these methods never actually escape the call context. Secondly, because we know everything is executed on the Workflow serial executor, we can also remove the @Sendable and sending requirements as (each of these closures are nonisolated(nonsending) by default now).

Modifications

• Removed @Sendable @escaping requirement from the timeout closure.
• Dropped the @escaping requirement for the workflow condition closure.
• Drop the sending @escaping requirement from the cancellation shield.

Test Plan

N/A