Fix declared license not in discovered license for certain cases

In some cases, CD (scancode summarizer) goes through the root files to
derive license information.  file.licenses is an array of licenses with
varying matching scores.  Currently, after the license file is found,
we concat all the license expressions as declared license (even though
some of them have low matching scores).  However, when the licenses are
tallied from the files, those licenses with score lower than 80 are
filtered out.  This inconsistency causes the declared license does not
show up in the discovered license (>80 score) in some cases.

Refactor the logic, so that only license score above 80 is considered
for declared license.

Test case:
https://clearlydefined.io/definitions/composer/packagist/colinmollenhour/cache-backend-redis/1.14.4

providers/summary/scancode.js

@@ -122,8 +122,8 @@ class ScanCodeSummarizer {
     const fullLicenses = files
       .filter(file => file.is_license_text && file.licenses)
       .reduce((licenses, file) => {
-        file.licenses.forEach(license => {
-          licenses.add(this._createExpressionFromLicense(license))
+        file.licenses.forEach((license) => {
+          if (this._isMatchedLicense(license)) licenses.add(this._createExpressionFromLicense(license))
         })
         return licenses
       }, new Set())
@@ -169,7 +169,9 @@ class ScanCodeSummarizer {
         const fileLicense = asserted || file.licenses || []
         let licenses = new Set(fileLicense.map(x => x.license).filter(x => x))
         if (!licenses.size)
-          licenses = new Set(fileLicense.filter(x => x.score >= 80).map(x => this._createExpressionFromLicense(x)))
+          licenses = new Set(
+            fileLicense.filter((x) => this._isMatchedLicense(x)).map((x) => this._createExpressionFromLicense(x))
+          )
         const licenseExpression = this._joinExpressions(licenses)
         setIfValue(result, 'license', licenseExpression)
         if (this._getLicenseByIsLicenseText([file]) || this._getLicenseByFileName([file], coordinates)) {
@@ -187,6 +189,10 @@ class ScanCodeSummarizer {
       .filter(e => e)
   }
 
+  _isMatchedLicense(license) {
+    return license.score >= 80
+  }
+
   _joinExpressions(expressions) {
     if (!expressions) return null
     const list = setToArray(expressions)