RAISE NOTICE in extension scripts is silently dropped by CREATE/ALTER EXTENSION

## Description

`pg_tle`'s install and update scripts contain seven `RAISE NOTICE` statements meant to inform operators about role creation, disabled feature GUCs, and misconfigured `passcheck_db_name` / `clientauth_db_name`. None of them ever reach the client, because Postgres's `execute_extension_script` clamps `client_min_messages` and `log_min_messages` to at least `WARNING` for the duration of `CREATE EXTENSION` and `ALTER EXTENSION UPDATE`.

## Steps to reproduce

1. `SET client_min_messages = notice;`
1. `CREATE ROLE pgtle_admin NOLOGIN;`
1. `CREATE EXTENSION pg_tle;`

## Expected outcome

```
NOTICE: Role "pgtle_admin" already exists. Skipping.
```

## Actual outcome

No output. The `NOTICE` is silently dropped by `execute_extension_script`'s severity clamp.

## Analysis

The same clamp affects all seven sites: `pg_tle--1.0.0.sql:281`, `pg_tle--1.0.4.sql:348`, `pg_tle--1.1.1.sql:340`, and `pg_tle--1.3.4--1.4.0.sql:91,95,103,106`.

Recommended fix: promote each `RAISE NOTICE` to `RAISE WARNING` — the lowest severity that survives the clamp — and update `test/expected/*.out` to match. I have a working patch with `make installcheck` green locally and can open a PR.

Start with the seven RAISE NOTICE sites named in pg_tle--1.0.0.sql, pg_tle--1.0.4.sql, pg_tle--1.1.1.sql, and pg_tle--1.3.4--1.4.0.sql. Review the corresponding test/expected/*.out files, then run make installcheck; done means the messages appear during extension creation or update and the expected outputs match.

Written by the indexing model from the issue text.