THREESCALE-12316: Fix deserialization with legacy --- HashWithIndifferentAccess

[mayorova]

What this PR does / why we need it:

There are might be some records in the DB which have hashes serialized with a legacy prefix !map:HashWithIndifferentAccess.

Which issue(s) this PR fixes

https://issues.redhat.com/browse/THREESCALE-12316

Verification steps

A simple way is to modify the data directly in the DB. For example, extra_fields in cinstances table. Example of legacy serialization:

--- !map:HashWithIndifferentAccess
custom_field: custom_value

Before the fix in this PR trying to load such application will fail.

After the fix, the applications are loaded OK. After saving the application, the serialization class is updated in the DB.

Special notes for your reviewer:

[qltysh]

❌ 3 blocking issues (3 total)

Tool	Category	Rule	Count
rubocop	Style	Incorrect formatting, autoformat by running qlty fmt.	1	❌
rubocop	Lint	Block has too many lines. [26/25]	1	❌
rubocop	Style	Align the arguments of a method call if they span more than one line.	1	❌

@qltysh one-click actions:

• Auto-fix formatting (qlty fmt && git push)