fix: EXPOSED-651 Try to close connection in ThreadLocalTransactionManager#connectionLazy if setup fails

[m-burst]

Description

Summary of the change: Try to close connection in ThreadLocalTransactionManager#connectionLazy if setup fails

Detailed description:

• What: The connection setup in ThreadLocalTransactionManager#connectionLazy now catches exceptions and attempts to close the database connection in case of an exception.
• Why: After the connection is obtained from the Database, Exposed tries to perform some initial setup before using the connection in a Transaction. If this setup fails, the connection is not closed (neither immediately nor when closing the transaction, because the connection is not stored inside the transaction due to lazy semantics), which in turn leads to connection leak.
• How: The setup code is wrapped in a try-catch block, which catches all exceptions and tries to close the connection before rethrowing.

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Type of Change

Please mark the relevant options with an "X":

• Bug fix
• New feature
• Documentation update

Updates/remove existing public API methods:

• Is breaking change

Affected databases:

• MariaDB
• Mysql5
• Mysql8
• Oracle
• Postgres (not sure which other databases are affected, but we ran into this problem with Postgres)
• SqlServer
• H2
• SQLite

Checklist

• Unit tests are in place — not sure how to test this, we used a heavily mocked java.sql.Driver to reproduce
• The build is green (including the Detekt check)
• All public methods affected by my PR has up to date API docs (no API changes)
• Documentation for my change is up to date — please let me know if documentation changes are needed

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Related Issues

EXPOSED-651

[joc-a]

Hi @m-burst. Thank you for your contribution. Please add a description to your pull request following the format that was set up when you first opened it as outlined here.

[m-burst]

Hi @joc-a, I've added the description