Add an option to disable LazyConnectionDataSourceProxy eager checkDefaultConnectionProperties call

[reda-alaoui]

Fix #29931

[reda-alaoui]

👋

[jhoeller]

After some back and forth, I ended up dropping the eager connection properties check completely, in favor of a late check on the first getConnection() call (but before exposing the Connection proxy, so still exposing consistent behavior for the consumer of the Connection proxy). As a consequence, there is no need for a configuration flag. If a startup-time check should be enforced (which we don't actually recommend these days), the new public checkDefaultConnectionProperties() method can be called. Even better would be to explicitly specify the defaultAutoCommit and defaultTransactionIsolation configuration settings.

I'll use the original ticket #29931 for that revision.