[JDBC] Honor DriverManager login timeout

[ennuite]

Describe the enhancement requested

ArrowFlightJdbcDriver.connect() does not currently honor the timeout configured through DriverManager.setLoginTimeout(int).

Implement support for the DriverManager login timeout:

• Read the value exposed by DriverManager.getLoginTimeout() when establishing a connection selected by DriverManager.
• Preserve the JDBC semantics of zero: do not impose a login timeout.
• Apply a nonzero timeout to the overall connection attempt, not only the underlying Netty socket connection.
• If the timeout expires, attempt to cancel the connection attempt and throw SQLTimeoutException.
• Clean up any allocator, channel, or partially constructed client when the attempt is cancelled or times out.
• Add tests that set and restore the global DriverManager timeout and verify timeout enforcement, exception type, and resource cleanup.

This is distinct from #494/#495. The existing connectTimeoutMs property configures Netty socket connection attempts and does not consume the timeout configured through DriverManager.

Context: #1027 and the follow-up discussion.

Related DataSource work: #1267