logical: external conn should not require db name

[kev-cao]

LDR currently erroneously requires the db name in the external connection with setting up a bidirectional connection. This was determined to be caused by the fact that the privilege lookup on the source cluster was using unqualified table names during the reverse stream setup. This commit fixes the issue by using fully qualified table names.

Fixes: #152395

Release note: LDR no longer requires the database name to be specified in the external connection URI when setting up a bidirectional stream.

[cockroach-teamcity]

This change is 

[Copilot]

Pull Request Overview

This PR fixes an issue where LDR (Logical Data Replication) incorrectly required a database name in external connection URIs when setting up bidirectional streams. The fix addresses privilege lookup problems during reverse stream setup by using fully qualified table names.

• Changed table name resolution to use fully qualified names instead of unqualified names
• Added test coverage to verify external connections work without database names in the URI

Reviewed Changes

Copilot reviewed 2 out of 2 changed files in this pull request and generated 2 comments.

File	Description
pkg/crosscluster/logical/create_logical_replication_stmt.go	Updated TargetTableNames() to return fully qualified table names using FQString() instead of Table()
pkg/crosscluster/logical/logical_replication_job_test.go	Added new test to verify bidirectional replication works without database name in external connection URI

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[msbutler]

Nice!

[msbutler]

bors r+

[craig]

Build succeeded:

• local_roachtest_fips
• check_generated_code
• docker_image_amd64
• linux_amd64_build
• acceptance
• linux_amd64_fips_build
• lint
• local_roachtest
• unit_tests
• examples_orms

[blathers-crl]

Based on the specified backports for this PR, I applied new labels to the following linked issue(s). Please adjust the labels as needed to match the branches actually affected by the issue(s), including adding any known older branches.

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Issue #152395: branch-release-25.2, branch-release-25.3, branch-release-25.4.

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