Sentry: XA in implicit txn caused panic

This issue was auto filed by Sentry. It represents a crash or reported error on a live cluster with telemetry enabled.

Sentry Link: [https://cockroach-labs.sentry.io/issues/7529381832/?referrer=webhooks_plugin](https://cockroach-labs.sentry.io/issues/7529381832/?referrer=webhooks_plugin)

Panic Message:

```
conn_executor.go:1054: ×
(1) attached stack trace
-- stack trace:
| github.com/cockroachdb/cockroach/pkg/sql.(*Server).ServeConn.func1
| pkg/sql/conn_executor.go:1054
| [...repeated from below...]
Wraps: (2) while executing: PREPARE TRANSACTION '_'
Wraps: (3) attached stack trace
-- stack trace:
| github.com/cockroachdb/cockroach/pkg/sql.(*Server).ServeConn.func1
| pkg/sql/conn_executor.go:1054
| runtime.gopanic
| GOROOT/src/runtime/panic.go:791
| github.com/cockroachdb/cockroach/pkg/sql.(*connExecutor).txnStateTransitionsApplyWrapper
| pkg/sql/conn_executor.go:4046
| github.com/cockroachdb/cockroach/pkg/sql.(*connExecutor).execCmd
| pkg/sql/conn_executor.go:2617
| github.com/cockroachdb/cockroach/pkg/sql.(*connExecutor).run
| pkg/sql/conn_executor.go:2278
| github.com/cockroachdb/cockroach/pkg/sql.(*Server).ServeConn
| pkg/sql/conn_executor.go:1056
| github.com/cockroachdb/cockroach/pkg/sql/pgwire.(*conn).processCommands
| pkg/sql/pgwire/conn.go:253
| github.com/cockroachdb/cockroach/pkg/sql/pgwire.(*Server).serveImpl.func4
| pkg/sql/pgwire/server.go:1214
| runtime.goexit
| src/runtime/asm_arm64.s:1223
Wraps: (4) ×
Error types: (1) *withstack.withStack (2) *safedetails.withSafeDetails (3) *withstack.withStack (4) *fsm.TransitionNotFoundError
-- report composition:
*fsm.TransitionNotFoundError
conn_executor.go:1054: *withstack.withStack (top exception)
*safedetails.withSafeDetails: while executing: PREPARE TRANSACTION '_'
conn_executor.go:1054: *withstack.withStack (1)
(check the extra data payloads)
```

Stacktrace (expand for inline code snippets):

[src/runtime/asm_arm64.s#L1222-L1224](src/runtime/asm_arm64.s#L1222-L1224)
[pkg/sql/pgwire/server.go#L1213-L1215](pkg/sql/pgwire/server.go#L1213-L1215)
[pkg/sql/pgwire/conn.go#L252-L254](pkg/sql/pgwire/conn.go#L252-L254)
[pkg/sql/conn_executor.go#L1055-L1057](pkg/sql/conn_executor.go#L1055-L1057)
[pkg/sql/conn_executor.go#L2277-L2279](pkg/sql/conn_executor.go#L2277-L2279)
[pkg/sql/conn_executor.go#L2616-L2618](pkg/sql/conn_executor.go#L2616-L2618)
[pkg/sql/conn_executor.go#L4045-L4047](pkg/sql/conn_executor.go#L4045-L4047)
[GOROOT/src/runtime/panic.go#L790-L792](GOROOT/src/runtime/panic.go#L790-L792)
[pkg/sql/conn_executor.go#L1053-L1055](pkg/sql/conn_executor.go#L1053-L1055)

```
src/runtime/asm_arm64.s in runtime.goexit at line 1223
pkg/sql/pgwire/server.go in pkg/sql/pgwire.(*Server).serveImpl.func4 at line 1214
pkg/sql/pgwire/conn.go in pkg/sql/pgwire.(*conn).processCommands at line 253
pkg/sql/conn_executor.go in pkg/sql.(*Server).ServeConn at line 1056
pkg/sql/conn_executor.go in pkg/sql.(*connExecutor).run at line 2278
pkg/sql/conn_executor.go in pkg/sql.(*connExecutor).execCmd at line 2617
pkg/sql/conn_executor.go in pkg/sql.(*connExecutor).txnStateTransitionsApplyWrapper at line 4046
GOROOT/src/runtime/panic.go in runtime.gopanic at line 791
pkg/sql/conn_executor.go in pkg/sql.(*Server).ServeConn.func1 at line 1054
```

### Tags

| Tag | Value |
| --- | --- |
| Command | start-single-node |
| Environment | v25.3.0 |
| Go Version | go1.23.7 X:nocoverageredesign |
| Platform | linux arm64 |
| Distribution | CCL |
| Cockroach Release | v25.3.0 |
| Cockroach SHA | cb540b101146345c1df9f265f65ea321c62b10b3 |
| # of CPUs | 1 |
| # of Goroutines | 385 |

Jira issue: CRDB-64564