chore: bump spec version and collator version

[ipapandinas]

Pull Request Summary

New prep release for runtime and client:

• collator release v5.48.0
• runtime release 2000

Contains the following changes:

1. PolkadotSDK Update (stable2506)
   2 major version bump (stable2412 → stable2503 → stable2506)
   Litep2p is now the default network stack (Libp2p still available via CLI flag)
2. Cleanups
   • Sudo pallet removal from Astar runtime
   • AssetHub migration code removed
   • Stale collator selection data cleanup
3. Bug Fix
   • dApp Staking invariant fix - corrects Ledger contract stake count tracking

[github-actions]

Package	Line Rate	Branch Rate	Health
pallets/dapp-staking/src	80%	0%	✔
pallets/dapp-staking/src/benchmarking	95%	0%	✔
precompiles/xcm/src	69%	0%	➖
pallets/inflation/src	58%	0%	➖
precompiles/assets-erc20/src	77%	0%	➖
primitives/src	55%	0%	➖
precompiles/dapp-staking/src	89%	0%	✔
pallets/collator-selection/src	82%	0%	✔
pallets/price-aggregator/src	75%	0%	➖
chain-extensions/unified-accounts/src	0%	0%	❌
pallets/ethereum-checked/src	76%	0%	➖
precompiles/substrate-ecdsa/src	67%	0%	➖
pallets/astar-xcm-benchmarks/src/fungible	100%	0%	✔
pallets/dynamic-evm-base-fee/src	82%	0%	✔
pallets/democracy-mbm/src	30%	0%	❌
pallets/vesting-mbm/src	87%	0%	✔
pallets/static-price-provider/src	91%	0%	✔
precompiles/unified-accounts/src	100%	0%	✔
precompiles/dispatch-lockdrop/src	83%	0%	✔
pallets/dapp-staking/rpc/runtime-api/src	0%	0%	❌
precompiles/sr25519/src	56%	0%	➖
pallets/dapp-staking/src/test	0%	0%	❌
pallets/collective-proxy/src	94%	0%	✔
pallets/astar-xcm-benchmarks/src/generic	100%	0%	✔
chain-extensions/types/unified-accounts/src	0%	0%	❌
primitives/src/xcm	66%	0%	➖
chain-extensions/pallet-assets/src	54%	0%	➖
pallets/unified-accounts/src	79%	0%	➖
chain-extensions/types/assets/src	0%	0%	❌
pallets/xc-asset-config/src	56%	0%	➖
precompiles/dapp-staking/src/test	0%	0%	❌
pallets/astar-xcm-benchmarks/src	86%	0%	✔
Summary	72% (3884 / 5383)	0% (0 / 0)	➖

Minimum allowed line rate is 50%