use new compute network to fix dbms private connection test

[BBBmau]

Fixes #17384

Since the test itself relies on a default network it attempts to use an ip address that has already been reserved resulting in an operation timeout. Solution Reference: hashicorp/terraform-provider-google#17384 (comment)

The chosen subnet ip comes from the docs themselves since we're using auto_create_subnetworks: https://cloud.google.com/vpc/docs/vpc#ip-ranges

Release Note Template for Downstream PRs (will be copied)

[modular-magician]

Hi there, I'm the Modular magician. I've detected the following information about your changes:

Diff report

Your PR generated some diffs in downstreams - here they are.

google provider: Diff ( 2 files changed, 14 insertions(+), 9 deletions(-))
google-beta provider: Diff ( 2 files changed, 14 insertions(+), 9 deletions(-))
Open in Cloud Shell: Diff ( 1 file changed, 7 insertions(+), 4 deletions(-))

[modular-magician]

Tests analytics

Total tests: 5
Passed tests: 4
Skipped tests: 0
Affected tests: 1

Click here to see the affected service packages

• databasemigrationservice

Action taken

Found 1 affected test(s) by replaying old test recordings. Starting RECORDING based on the most recent commit. Click here to see the affected tests

TestAccDatabaseMigrationServicePrivateConnection_databaseMigrationServicePrivateConnectionExample

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[modular-magician]

$\textcolor{red}{\textsf{Tests failed during RECORDING mode:}}$
TestAccDatabaseMigrationServicePrivateConnection_databaseMigrationServicePrivateConnectionExample[Error message] [Debug log]

$\textcolor{red}{\textsf{Please fix these to complete your PR.}}$
View the build log or the debug log for each test