Server Audit does not escape newline/tab in user, host, database or table identifiers, allowing forged log lines

The audit plugin escapes the query text before writing a QUERY record (the fix from MDEV-8032),
but it writes `user`, `host`, database and table identifiers using plain `%.*s`. MariaDB
identifiers may legally contain newline and tab characters (`sql/table.cc:5527-5549` only rejects
NUL and a trailing space), so an object name containing `\n` is written verbatim into the audit
log. The file logger appends the record and `'\n'` without post-processing, so one audit record
becomes several lines and an attacker with CREATE privileges can inject plausible-looking
records (CWE-117 log forging) or corrupt CSV/SIEM parsing.

Steps to reproduce

```bash
IMG='mariadb@sha256:dd9b303aed4f4890ed09f766d8ca9ddfd176c0c6f6267feff53b3192ec65a979'
docker run -d --name mdev-audit-id --env MARIADB_ALLOW_EMPTY_ROOT_PASSWORD=yes "$IMG" \
--skip-name-resolve --log-error=/var/lib/mysql/error.log

1. wait for readiness, then:
   docker exec mdev-audit-id mariadb --socket=/run/mysqld/mysqld.sock -uroot -e "
   INSTALL SONAME 'server_audit';
   SET GLOBAL server_audit_logging=ON;
   SET GLOBAL server_audit_events='CONNECT,QUERY,QUERY_DCL,TABLE';
   SET GLOBAL server_audit_file_path='/var/lib/mysql/audit.log';
   CREATE DATABASE dsh37;
   CREATE TABLE dsh37.normal_t (i INT);
   INSERT INTO dsh37.normal_t VALUES (1);"
2. table name with a real newline (use a file to keep shell quoting simple):
   printf 'CREATE TABLE `dsh37`.`evil\ntbl` (i INT); INSERT INTO `dsh37`.`evil\ntbl` VALUES (2);\n' > /tmp/nl.sql
   docker exec -i mdev-audit-id mariadb --socket=/run/mysqld/mysqld.sock -uroot < /tmp/nl.sql
   docker exec mdev-audit-id tail -20 /var/lib/mysql/audit.log

Actual result

The normal table produces well-formed single-line records. The newline-bearing table produces a
TABLE/QUERY record whose identifier breaks the record across lines; the continuation line starts
with the table-name fragment (here `tbl,`), i.e. an injected line that is not a valid audit
record but is written to the same log:

```text
20261025 18:17:26,...,root,localhost,7,11,CREATE,dsh37,normal_t,
20261025 18:17:26,...,root,localhost,7,12,WRITE,dsh37,normal_t,
...
20261025 18:17:26,...,root,localhost,8,14,CREATE,dsh37,evil
tbl,
```

Expected result

Control characters in identifiers should be escaped like they are in query text (for example to
`\n`/`\t` sequences or percent-encoded), so each audit event occupies exactly one line and the
fields remain parseable.