`\ef` in a transaction causes pgcli to crash

## Description

If a transaction is manually started (`begin transaction;`) then an attempt to edit a postgres function or stored procedure is made via `\ef function_name`, pgcli will crash.

Expected behavior: Although it is a postgres error to try to edit a function within a transaction, pgcli should not crash.

## Your environment
* FreeBSD 13.1
* pgcli 3.5.0
* postgres 14.6

`pip freeze` output:

acme==2.1.0

awscli==1.27.16

botocore==1.29.13

certbot==2.1.0

certbot-nginx==2.1.0

certifi==2022.9.24

cffi==1.15.1

charset-normalizer==3.0.1

cli-helpers==2.3.0

click==8.0.3

colorama==0.4.5

ConfigArgParse==1.5.3

configobj==5.0.6

cryptography==3.4.8

distro==1.8.0

dnspython==2.2.1

docutils==0.17.1

idna==3.4

importlib-metadata==4.8.1

jmespath==1.0.1

josepy==1.13.0

Markdown==3.3.7

parsedatetime==2.6

pendulum==2.1.2

pgcli==3.5.0

pgspecial==2.0.1

prompt-toolkit==3.0.36

psycopg==3.1.7

psycopg-pool==3.1.4

pyasn1==0.4.8

pycparser==2.21

Pygments==2.14.0

pyOpenSSL==20.0.1

pyparsing==3.0.9

pyRFC3339==1.1

PySocks==1.7.1

python-dateutil==2.8.2

pytz==2022.7

pytzdata==2020.1

PyYAML==5.4.1

requests==2.28.1

rsa==4.9

s3transfer==0.6.0

setproctitle==1.3.2

six==1.16.0

sqlparse==0.4.3

tabulate==0.8.9

typing-extensions==4.4.0

urllib3==1.26.13

wcwidth==0.1.8

zipp==3.4.0

- [X] Please provide your OS and version information.
- [X] Please provide your CLI version.
- [X] What is the output of ``pip freeze`` command.