linera-client: make sure to use linera_base::time (#3257)

## Motivation

`std::time` will panic if used on `wasm32-unknown-unknown`, since
without making additional assumptions about the execution environment no
clock syscalls can be used. A `std::time::Duration` is used in
`linera_client::client_options`.

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## Proposal

We have time primitives exported from `linera_base::time` that are
Web-safe (using `web-time` on the Web). Replace `std::time::Duration`
with `linera_base::time::Duration` in `linera-client`.

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above.
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## Test Plan

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## Release Plan

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- Nothing to do / These changes follow the usual release cycle.

## Links

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- [reviewer
checklist](https://github.com/linera-io/linera-protocol/blob/main/CONTRIBUTING.md#reviewer-checklist)

linera-client/src/client_options.rs

@@ -6,7 +6,6 @@ use std::{
     env, fmt, iter,
     num::{NonZeroU16, NonZeroUsize},
     path::PathBuf,
-    time::Duration,
 };
 
 use chrono::{DateTime, Utc};
@@ -17,6 +16,7 @@ use linera_base::{
         Account, ApplicationId, BytecodeId, ChainId, MessageId, Owner, UserApplicationId,
     },
     ownership::{ChainOwnership, TimeoutConfig},
+    time::Duration,
 };
 use linera_core::{client::BlanketMessagePolicy, DEFAULT_GRACE_PERIOD};
 use linera_execution::{