chore(deps): upgrade Scalar from 0.5.55 to 0.6.71 (#3359)

[Naresh7175]

What

Bumps the scalar.version property in the root pom.xml from 0.5.55
to 0.6.71. This single property drives all four Scalar Maven artifacts
(scalar, scalar-core, scalar-webmvc, scalar-webflux) via
dependencyManagement.

Why

The pinned Scalar version had drifted significantly behind upstream
releases, while swagger-ui has been kept current on every springdoc
release. Fixes #3359.

Verification

Manually verified locally with a Spring Boot test app, comparing
springdoc-openapi 3.1.1 (Scalar 0.5.55) against this patch (Scalar
0.6.71) side by side on separate ports:

• mvn dependency:tree confirms the version resolves correctly
• Module tests pass for springdoc-openapi-starter-webmvc-scalar and
  springdoc-openapi-starter-webflux-scalar
• No functional regressions in request execution or schema rendering
• Nested object schemas now render inline with fields visible
  (e.g. address AddressDTO { city, zip }) instead of requiring a
  click to expand
• Enum values render compactly ("ACTIVE" or "INACTIVE" or "PENDING" · enum)
  instead of an expanded list
• Note: the model deep-link URL fragment format changed between
  versions (#model/name → #models/Name), which may affect any
  bookmarked/shared links to specific model anchors

please find the attached screenshots.

[Naresh7175]

Hi @bnasslahsen, Could you please review the PR and merge it.

This PR will Fixes - #3359