fix(catalog): URL-encode entity_name slashes in entity tag paths

[jaideeppyne]

Problem

Unity Catalog allows entity names that contain / (e.g. a column named `Inferences/Second`). The Entity Tag Assignments API treats entity_name as a single path segment, so / must be percent-encoded as %2F.

EntityTagAssignmentsAPI currently interpolates entity_name (and tag_key) into the path without encoding. A raw / splits the path, matches no route, and fails with NotFound: No API found ....

Solution

• Add _escape_path_parameter() that uses urllib.parse.quote(param, safe="") so / becomes %2F (unlike _escape_multi_segment_path_parameter, which intentionally preserves / for Files API paths).
• Apply it to entity_name and tag_key in EntityTagAssignmentsAPI (list / get / delete / update).

Testing

• Unit tests for _escape_path_parameter (/ → %2F, FQN with slash, other reserved chars).
• Unit tests asserting EntityTagAssignmentsAPI.list/get/delete call _api.do with %2F in the path.

Fixes #1493

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Inputs:

• PR number: 1575
• Commit SHA: 07e14793bbf3900be14d89829d5ed82c209485c9

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