Add Baklava migration block

[palango]

Description

Adds the Baklava migration block.

Resolves https://github.com/celo-org/celo-blockchain-planning/issues/884

[github-actions]

Coverage from tests in ./e2e_test/... for ./consensus/istanbul/... at commit 6a9b47d

coverage: 55.3% of statements across all listed packages

coverage:  68.4% of statements in consensus/istanbul
coverage:  63.5% of statements in consensus/istanbul/announce
coverage:  57.5% of statements in consensus/istanbul/backend
coverage:   0.0% of statements in consensus/istanbul/backend/backendtest
coverage:  24.3% of statements in consensus/istanbul/backend/internal/replica
coverage:  66.2% of statements in consensus/istanbul/core
coverage:  50.0% of statements in consensus/istanbul/db
coverage:   0.0% of statements in consensus/istanbul/proxy
coverage:  64.2% of statements in consensus/istanbul/uptime
coverage:  52.4% of statements in consensus/istanbul/validator
coverage:  79.2% of statements in consensus/istanbul/validator/random

[github-actions]

Test failures:
TestTransactionIndices: core Failed blockchain_test.go:1946: Oldest indexded block mismatch, want 69, have 100
This test report was produced by the test-summary action.  Made with ❤️ in Cambridge.

[gastonponti]

LGTM
Just as a double check, this block with my numbers will be on Feb 20 2025 16:13:25 PM (+01:00 UTC)

[palango]

Yes, that's good.