[VPC]: Fix security group assignment for opentelekomcloud_networking_port_v2

[artem-lifshits]

Summary of the Pull Request

Security group assignment fixed in cases when it's provided

PR Checklist

• Refers to: #OTC Community
• Tests added/passed.
• Release notes added.

Acceptance Steps Performed

=== RUN   TestAccNetworkingV2Port_basic
=== PAUSE TestAccNetworkingV2Port_basic
=== CONT  TestAccNetworkingV2Port_basic
--- PASS: TestAccNetworkingV2Port_basic (70.19s)
=== RUN   TestAccNetworkingV2Port_importBasic
=== PAUSE TestAccNetworkingV2Port_importBasic
=== CONT  TestAccNetworkingV2Port_importBasic
--- PASS: TestAccNetworkingV2Port_importBasic (76.19s)
=== RUN   TestAccNetworkingV2Port_noip
=== PAUSE TestAccNetworkingV2Port_noip
=== CONT  TestAccNetworkingV2Port_noip
--- PASS: TestAccNetworkingV2Port_noip (69.66s)
=== RUN   TestAccNetworkingV2Port_allowedAddressPairs
=== PAUSE TestAccNetworkingV2Port_allowedAddressPairs
=== CONT  TestAccNetworkingV2Port_allowedAddressPairs
--- PASS: TestAccNetworkingV2Port_allowedAddressPairs (87.75s)
=== RUN   TestAccNetworkingV2Port_portSecurity_enabled
=== PAUSE TestAccNetworkingV2Port_portSecurity_enabled
=== CONT  TestAccNetworkingV2Port_portSecurity_enabled
--- PASS: TestAccNetworkingV2Port_portSecurity_enabled (88.15s)
=== RUN   TestAccNetworkingV2Port_noPortSecurityNoSecurityGroups
=== PAUSE TestAccNetworkingV2Port_noPortSecurityNoSecurityGroups
=== CONT  TestAccNetworkingV2Port_noPortSecurityNoSecurityGroups
--- PASS: TestAccNetworkingV2Port_noPortSecurityNoSecurityGroups (68.98s)
=== RUN   TestAccNetworkingV2Port_timeout
=== PAUSE TestAccNetworkingV2Port_timeout
=== CONT  TestAccNetworkingV2Port_timeout
--- PASS: TestAccNetworkingV2Port_timeout (70.31s)
PASS

Process finished with the exit code 0

[otc-zuul]

Build succeeded.
https://zuul.otc-service.com/t/eco/buildset/42827b261b8c469698de67d98ff31cef

✔️ build-otc-releasenotes SUCCESS in 4m 59s
✔️ otc-golangci-lint SUCCESS in 3m 19s
✔️ golang-make-test SUCCESS in 4m 39s
✔️ golang-make-vet SUCCESS in 3m 36s
✔️ tflint SUCCESS in 3m 56s
✔️ goreleaser-build SUCCESS in 7m 01s