fix: emit NOASSERTION for copyright text to fix SPDX 2.2 validation failure (#3495)

* fixes issue #3346

Signed-off-by: Fearkin <fearjin1@gmail.com>

* chore: update schema and unit tests to reflect new copyright property

Signed-off-by: Christopher Phillips <32073428+spiffcs@users.noreply.github.com>

* chore: revert schema changes

Signed-off-by: Christopher Phillips <32073428+spiffcs@users.noreply.github.com>

* fix: noassert copyright on spdx root package

Signed-off-by: Will Murphy <willmurphyscode@users.noreply.github.com>

* test: explicitly test spdx 2.2 with tools-java validator

Signed-off-by: Will Murphy <willmurphyscode@users.noreply.github.com>

* test: update snapshot files

Signed-off-by: Will Murphy <willmurphyscode@users.noreply.github.com>

---------

Signed-off-by: Fearkin <fearjin1@gmail.com>
Signed-off-by: Christopher Phillips <32073428+spiffcs@users.noreply.github.com>
Signed-off-by: Will Murphy <willmurphyscode@users.noreply.github.com>
Co-authored-by: Fearkin <fearjin1@gmail.com>
Co-authored-by: Will Murphy <willmurphyscode@users.noreply.github.com>

syft/format/spdxjson/test-fixtures/snapshot/TestSPDX22JSONRequredProperties.golden

@@ -48,7 +48,7 @@
   },
   {
    "SPDXID": "SPDXRef-DocumentRoot-Unknown-",
-   "copyrightText": "",
+   "copyrightText": "NOASSERTION",
    "downloadLocation": "NOASSERTION",
    "filesAnalyzed": false,
    "licenseConcluded": "NOASSERTION",
@@ -71,7 +71,7 @@
    "licenseInfoInFiles": [
     "NOASSERTION"
    ],
-   "copyrightText": "",
+   "copyrightText": "NOASSERTION",
    "comment": "layerID: ac897d978b6c38749a1"
   }
  ],