Breaking: #82852 - Exception is thrown on invalid charset 

See forge#82852

Description 

The method \TYPO3\CMS\Core\Charset\CharsetConverter::initCharset() and consequently all methods in this class calling that method now throw an \TYPO3\CMS\Core\Charset\UnknownCharsetException if an unknown charset was provided.

The TypoScriptFrontendController aka TSFE uses this to throw a \RuntimeException in case of an invalid config.metaCharset. Before this resulted in a blank page instead.

Impact 

Third party code directly using the CharsetConverter class need to be aware of the new exception in case of an invalid charset.

Sites with an invalid config.metaCharset will now see a clear error message.

Migration 

Catch the UnknownCharsetException of the CharsetConverter if necessary.

Ensure that config.metaCharset is set to a known charset.