refactor: convert pg commands to esm part 8

[erika-wallace]

Description

W-19701088

This PR converts the following pg commands and their associated tests to ESM.

Converted commands:

• connection-pooling/attach.ts
• credentials/create.ts
• credentials/destroy.ts
• credentials/repair-default.ts
• credentials/rotate.ts
• credentials/url.ts

Notable Changes

• Added essentialPlan() helper in lib/pg/util.ts to centralize essential tier checks (both legacy and numbered essential plans) and avoid repeating isLegacyEssentialDatabase() || isEssentialDatabase() throughout the codebase
• Updated tests to use mini instead of deprecated hobby-dev plan

Testing

Manually test commands:

• Requires a Standard-tier or higher Postgres database.

Pull down branch, npm install && npm run build

# Show converted command topics
./bin/run pg --help

# Show default credential URL
./bin/run pg:credentials:url -a $APP

# Create a test credential
./bin/run pg:credentials:create -n test-cred -a $APP

# Show the test credential URL
./bin/run pg:credentials:url -n test-cred -a $APP

# Rotate the test credential
./bin/run pg:credentials:rotate -n test-cred -a $APP

# Repair default credential permissions
./bin/run pg:credentials:repair-default -a $APP

# Attach connection pooling
./bin/run pg:connection-pooling:attach -a $APP

# Detach connection pooling
./bin/run addons:detach <ATTACHMENT_NAME> -a $APP

# Destroy the test credential
./bin/run pg:credentials:destroy -n test-cred -a $APP

[k80bowman]

Just one question in a couple of places, but otherwise this looks good.

[k80bowman]

Looks good, thank you for the changes!