storage: set format major verison for v25.3

[jbowens]

Set the storage engine's format major version for cluster version v25.3.

Epic: none Release note: None

[blathers-crl[bot]]

It looks like your PR touches production code but doesn't add or edit any test code. Did you consider adding tests to your PR?

_{:owl: Hoot! I am a Blathers, a bot for CockroachDB. My owner is dev-inf.}

[cockroach-teamcity]

This change is 

[jbowens]

TFTR!

bors r=RaduBerinde

[craig[bot]]

Build succeeded:

• unit_tests
• local_roachtest
• lint
• linux_amd64_build
• acceptance
• docker_image_amd64
• local_roachtest_fips
• examples_orms
• linux_amd64_fips_build
• check_generated_code