fix: close streams in LoggerContextAdmin.setConfigLocationUri

[SebTardif]

What Problem This Solves

LoggerContextAdmin.setConfigLocationUri opened a FileInputStream or URL stream and passed it to ConfigurationSource(InputStream, File/URL). That constructor documents that the caller owns the stream. On some failure paths before the configuration parser closes the stream, the descriptor can leak. Same theme as the ConfigurationSource URL leak work in #4127.

Evidence

Failure scenario

configSource = new ConfigurationSource(new FileInputStream(configFile), configFile);
// if getConfiguration/start fails before the config impl closes the stream,
// the FileInputStream remains open

Fix

Buffer the configuration into memory with try-with-resources, then construct a ConfigurationSource(Source, byte[], lastModified) that owns a ByteArrayInputStream.

Red-green / tests

export JAVA_HOME=$(/usr/libexec/java_home -v 17)
./mvnw -pl log4j-core,log4j-core-test -am test \
  -Dtest=LoggerContextAdminSetConfigLocationUriTest \
  -Dsurefire.failIfNoSpecifiedTests=false

Result: 3 tests pass (valid file reconfigure, file: URL form, blank rejection).

Summary

• Buffer + close file/URL streams in setConfigLocationUri
• Regression tests in LoggerContextAdminSetConfigLocationUriTest
• Changelog entry