Resolve "INH values for filtered variants disappears"

Description

Added loading-flag to excluded allele modal state, that is used to disable buttons until showAddExcludedAllelesClicked signal completes.

Also: Reset modal state when closed.

Related issues

Notes to review (code/docs/QA)

Tests

General

• Tests have been added that prove my fix is effective or that my feature works
• Related tests have been modified/removed

Hypothesis testing:

• Soak testing has been done
• Distribution between positive / negative cases has been checked

Database

• Includes changes to database schema
• Includes necessary database migrations

Configuration

• Includes changes to configuration
• Includes configuration migration instructions in documentation

Closes #1980 (closed)