feat: add business_hours support for sla evaluation

[vishnu-narayanan]

Pull Request Template

Description

• Add support for respecting the business_hour setting in SLA policies

Changelog

• Business hours are used in evaluation only if the inbox configures business hours and a conversation is applied with an SLA policy that has only_during_business_hours set to true.
• If either inbox or sla_poliicy is missing business_hours, this will be evaluated normally

Fixes https://linear.app/chatwoot/issue/CW-3051/handle-business-hours-during-sla-evaluation

Type of change

Please delete options that are not relevant.

• New feature (non-breaking change which adds functionality)

How Has This Been Tested?

• Add new specs

Checklist:

• My code follows the style guidelines of this project
• I have performed a self-review of my code
• I have commented on my code, particularly in hard-to-understand areas
• I have made corresponding changes to the documentation
• My changes generate no new warnings
• I have added tests that prove my fix is effective or that my feature works
• New and existing unit tests pass locally with my changes
• Any dependent changes have been merged and published in downstream modules

[linear]

CW-3051 Handle business hours during SLA evaluation

[github-actions]

🐢 Turtley slow progress alert! This pull request has been idle for over 30 days. Can we please speed things up and either merge it or release it back into the wild?

[Sergezdv]

17:46:48 worker.1   | Error performing Sla::ProcessAppliedSlaJob ... TypeError (WorkingHours::Duration can't be coerced into Integer):
17:46:48 worker.1   | /enterprise/app/services/sla/evaluate_applied_sla_service.rb:57:in `+'
17:46:48 worker.1   | /enterprise/app/services/sla/evaluate_applied_sla_service.rb:57:in `calculate_threshold'
17:46:48 worker.1   | /enterprise/app/services/sla/evaluate_applied_sla_service.rb:67:in `check_first_response_time_threshold'
17:46:48 worker.1   | /enterprise/app/services/sla/evaluate_applied_sla_service.rb:45:in `block in check_sla_thresholds'

maybe
threshold_seconds.working.seconds.since(start_time).to_i
instead
start_time.to_i + threshold_seconds.working.seconds

[github-actions]

🐢 Turtley slow progress alert! This pull request has been idle for over 30 days. Can we please speed things up and either merge it or release it back into the wild?