Fixed local dependent writing of banner into ByteArrayOutputStream

[totti-dev]

Curently the printing of the banner in log mode (spring.main.banner-mode="log") only works correctly (correctly = displays unicode characters the correct way, without surrogate glyphs) if spring.banner.charset matches file.encoding. The banner is read using the encoding specified by "spring.banner.charset", before it is written in a local dependent way (dependent on file.encoding) into the ByteArrayOutputStream. After that it is re-read using the original "spring.banner.charset". This leads to unwanted replacements.

Proposed Solution -> Write banner into ByteArrayOutputStream using the original encoding and not the local dependent encoding.

Affected method: "createStringFromBanner(Banner banner, Environment environment, Class<?> mainApplicationClass)"

Local dependent writing by using PrintStream constructor with single argument (no encoding specified) "banner.printBanner(environment, mainApplicationClass, new PrintStream(baos));"

[pivotal-cla]

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[pivotal-cla]

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[mhalbritter]

Thank you very much and congratulations on your first contribution :tada:!