Update locals.tf - fixing 1.2.0 bug - null error in locals.tf when AzFW tags not defined

[cbezenco]

Getting a null error assignment on following tags assignment when no tags provided for Azure FW. Fixing using try() sequence.

Describe your changes

Fixing using try(value, null) sequence on firewalls.fw_default_ip_configuration_pip.tag and firewalls.fw_management_ip_configuration_pip.tag values assignment.

Issue number

#83

Checklist before requesting a review

• The pr title can be used to describe what this pr did in CHANGELOG.md file
• I have executed pre-commit on my machine
• I have passed pr-check on my machine

Thanks for your cooperation!