SDK 0.4.32: retry pre-dispatch capacity waits and draining deletes

Retry capacity waits the gateway reports before dispatching anything, until the operation deadline: wake_destination_unavailable (a parked sandbox found no wake capacity, e.g. on a CPU-saturated node) and migration_destination_unavailable. Previously an exec that woke a parked sandbox gave up after 6 attempts; in a 500-sandbox load test 12 sandboxes failed a turn this way.

Retry DELETE /v1/sandboxes/ while the node reports memory_publication_draining (a just-parked sandbox is still uploading its memory); deletes are idempotent.

The new server-side codes ship in ucloud-sandboxes 0.5.114rc58.