Stop passing Item.ANY as the language when writing metadata

[kosarko]

Description

In several CLARIN-specific code paths we call addMetadata(...) /
setMetadataSingleValue(...) with Item.ANY ("*") in the language
parameter. Item.ANY is a read wildcard ("match any language"); as a value it
is not a legal language and ends up stored verbatim in
metadatavalue.text_lang.

Consequences of the rows this produced:

• metadata-export writes those columns as dc.rights[*], local.files.count[*], …
• metadata-import rejects such a header outright since DSpace 7.6.3
  (MetadataImportInvalidHeadingException: Language ANY (*) was found in the heading …), so an export → import round trip of an affected item fails — see Not able to import metadata with metadata-import script - for the CSV file, exported with metadata-export. #1402.
• Before that check existed, the same CSV could silently clear metadata when a
  field had both a [*] and a no-language column
  (upstream CSV Import / Export can clear metadata if there are metadata values with language * DSpace/DSpace#9701).

Since the 7.6.5 upgrade (#1031) MetadataValue.setLanguage() normalizes "*" → null,
so new writes are harmless. The call sites are still wrong, they mislead the
next reader, and the historical rows they created need a separate data fix (#1406).

Call sites

All verified absent from upstream dspace-7.6.5 — these are ours.

file	lines	field(s) written
dspace-api/.../content/clarin/ClarinLicenseServiceImpl.java	120, 122, 124	dc.rights.uri, dc.rights, dc.rights.label
dspace-api/.../content/clarin/ClarinItemServiceImpl.java	183, 185, 187, 188	local.has.files, local.files.count, local.files.size
dspace-api/.../content/clarin/ClarinItemServiceImpl.java	249, 253	dc.date.issued
dspace-api/.../app/itemupdate/ItemFilesMetadataRepair.java	221, 223, 225	local.has.files, local.files.count, local.files.size
dspace-api/.../app/itemimport/ItemImportServiceImpl.java	730	dc.rights.label
dspace-api/.../versioning/DefaultItemVersionProvider.java	146	dc.title
dspace-server-webapp/.../app/rest/repository/HandleRestRepository.java	261, 270	dc.identifier.other, dc.identifier.uri
dspace-server-webapp/.../app/rest/submit/step/DescribeStep.java	151	default <value> of any submission-form field

Two things to watch when fixing

1. clearMetadata(..., Item.ANY) is correct and must stay. There Item.ANY is
   the wildcard "delete in every language" — e.g.
   ClarinLicenseServiceImpl.clearLicenseMetadataFromItem(). A find/replace across
   these files would narrow those deletes and strand old values. Only the
   write argument is wrong.

2. DefaultItemVersionProvider.java:146 is not a simple swap.
   setMetadataSingleValue(ctx, dso, schema, element, qualifier, language, value)
   (DSpaceObjectServiceImpl:471-474) passes the single language argument to
   both the clear and the add, so Item.ANY currently means "clear the title in
   every language, then add it with language *". Replacing it with null also
   narrows the clear. It should be split into an explicit
   clearMetadata(..., Item.ANY) followed by addMetadata(..., null, ...).

Definition of done

• No Item.ANY remains in a language argument of addMetadata /
  setMetadataSingleValue / addAndShiftRightMetadata in src/main.
• DefaultItemVersionProvider keeps its "clear all languages" behaviour.
• A checkstyle/CI-visible guard would be nice-to-have but is not required.

Related: #1402 (the symptom), upstream DSpace#9701 / DSpace#9710.
#1406 covers normalizing the text_lang = '*' rows already in the DB.