[7.x.x] Correct issue with boolean evaluation in predicates

[Robin6939]

Description:

Issues:
Closes eXist-db/exist#4958
Closes eXist-db/exist#4810

What

• Return false instead of () in GeneralComparison when no operands match (#4958).
• Update Predicate to handle the boolean correctly (#4810).
• Add license header includes/excludes in exist-core/pom.xml and ran mvn license:format.

Why

• Empty sequence was semantically wrong here; spec-compliant boolean result is false.
• Predicate logic needed to align with the new return semantics.
• License headers required by project policy.

How

• Modified GeneralComparison.java and Predicate.java.
• Adjusted emptySeq.xq and startWithComp.xq.
• Inserted include/exclude entries in the correct pom.xml sections (order preserved).
• Amended commits so each file’s license change appears in the first commit touching it.

Reference:

XPath 3.1 is explicit: a general comparison must return true or false, never a node sequence. See: 3.7.2 General comparison

Tests:

Added a couple of test cases

• exist-core/src/test/xquery/startWithComp.xq
• exist-core/src/test/xquery/emptySeq.xq

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