fix: initialize orphaned blocks on failed connection check during des…

[periperidev]

Body:

The basics

• I validated my changes

The details

Resolves

Fixes #9266

Proposed Changes

When a child block fails to connect to its parent during deserialization (e.g. due to a type check mismatch), the block
becomes an invisible "ghost" — it exists in the workspace data but has no SVG.

This PR fixes both deserialization paths:

• XML path (core/xml.ts): After initializing descendants, detect orphaned blocks (new top-level blocks that aren't
  descendants of the top block) and call initSvg() on them.
• JSON path (core/serialization/blocks.ts): Log a warning instead of throwing BadConnectionCheck for non-shadow
  blocks, allowing initBlock() to run. Shadow blocks still throw.

Both paths mark orphaned blocks as disabled via setDisabledReason(true, 'orphaned_connection_check').

Reason for Changes

When block definitions change (e.g. an input type changes from Long to Int), saved workspaces may contain blocks with
stale connection types. Currently these blocks become invisible ghosts that trigger validation errors. After this fix, they
appear as visible, disabled, detached top-level blocks.

Test Coverage

• 2 new tests in xml_test.js — rendered and headless workspace orphan initialization
• Updated "Bad checks" test in jso_deserialization_test.js to assert orphan behavior instead of throw
• 1 new rendered workspace SVG test in jso_deserialization_test.js
• All existing mocha tests pass (0 failures)

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