bootstrap: remove 25.2 bootstrap data

Part of the quarterly M.4 "Bump MinSupported" task as outlined in
`pkg/clusterversion/README.md`.

This commit removes the bootstrap data for v25.2, which is now below the
minimum supported version after bumping MinSupported from v25.2 to v25.3.

The bootstrap data files are used to initialize clusters at specific
versions. Since clusters can no longer start at v25.2 (it's below
MinSupported), these files are no longer needed.

Changes:
- Removed 25_2_system.keys and 25_2_system.sha256
- Removed 25_2_tenant.keys and 25_2_tenant.sha256
- Removed V25_2 entry from initialValuesFactoryByKey map in initial_values.go
- Removed go:embed variables for v25.2 bootstrap data
- Updated BUILD.bazel to remove embedsrcs for deleted files

Part of #147634 (reference PR for this quarterly task).

Release note: None

🤖 Generated with [Claude Code](https://claude.com/claude-code)

Co-Authored-By: Claude <[email protected]>

Author: celiala

pkg/sql/catalog/bootstrap/BUILD.bazel

@@ -8,10 +8,6 @@ go_library(
         "metadata.go",
     ],
     embedsrcs = [
-        "data/25_2_system.keys",
-        "data/25_2_system.sha256",
-        "data/25_2_tenant.keys",
-        "data/25_2_tenant.sha256",
         "data/25_3_system.keys",
         "data/25_3_system.sha256",
         "data/25_3_tenant.keys",

pkg/sql/catalog/bootstrap/data/25_2_system.keys

@@ -66,13 +66,6 @@ type initialValuesFactoryFn = func(opts InitialValuesOpts) (
 var initialValuesFactoryByKey = map[clusterversion.Key]initialValuesFactoryFn{
 	clusterversion.Latest: buildLatestInitialValues,
 
-	clusterversion.V25_2: hardCodedInitialValues{
-		system:        v25_2_system_keys,
-		systemHash:    v25_2_system_sha256,
-		nonSystem:     v25_2_tenant_keys,
-		nonSystemHash: v25_2_tenant_sha256,
-	}.build,
-
 	clusterversion.V25_3: hardCodedInitialValues{
 		system:        v25_3_system_keys,
 		systemHash:    v25_3_system_sha256,
@@ -144,18 +137,6 @@ func (f hardCodedInitialValues) build(
 // These files can be auto-generated for the latest version with the
 // sql-bootstrap-data CLI tool (see pkg/cmd/sql-bootstrap-data).
 
-//go:embed data/25_2_system.keys
-var v25_2_system_keys string
-
-//go:embed data/25_2_system.sha256
-var v25_2_system_sha256 string
-
-//go:embed data/25_2_tenant.keys
-var v25_2_tenant_keys string
-
-//go:embed data/25_2_tenant.sha256
-var v25_2_tenant_sha256 string
-
 //go:embed data/25_3_system.keys
 var v25_3_system_keys string