[FEATURE REQ] Support new version of 'jackson-dataformat-xml'

[Netyyyy]

Is your feature request related to a problem? Please describe.
Refer to FasterXML/jackson-dataformat-xml#584, when upgrating jackson-dataformat-xml to 2.14.2 or above, this

azure-sdk-for-java/sdk/core/azure-core/src/test/resources/GetXMLWithAttributes.xml

Line 18 in 5e5831a

<item/>

would be parse to null not empty, which would cause this line failed, expect is "" and actual is null.

azure-sdk-for-java/sdk/core/azure-core/src/test/java/com/azure/core/http/rest/RestProxyXMLTests.java

Line 196 in 5e5831a

assertEquals("", slideshow.slides()[1].items()[1]);

Describe the solution you'd like
Update GetXMLWithAttributes.xml for supporting jackson-dataformat-xml new version
Update to <item></item>

Describe alternatives you've considered
A clear and concise description of any alternative solutions or features you've considered.

Information Checklist
Kindly make sure that you have added all the following information above and checkoff the required fields otherwise we will treat the issuer as an incomplete report

• Description Added
• Expected solution specified

[Netyyyy]

@alzimmermsft please help take a look, thanks!

[alzimmermsft]

Thanks for filing this @Netyyyy, I'll take a look at this today and reply back later