the metadata files should be update when re-generation

[skywing918]

After the initial generation, metadata files (such as metadata.json, README.md, etc.) are created,
but when re-generation, these metadata files are not updated. This leads to inconsistencies

The expected behavior is that repeated generation should consistently refresh and update relevant fields in these metadata files, to ensure they always reflect the latest generated state.

• client name

[kazrael2119]

update client name will impact:

1. readme Azure/azure-sdk-for-js@45f4b2f#diff-9dd24c0d2d44c0adbdd50e4b24c4aec46981f010533a0796a4bbcefb15dcdcca
2. snippets test file Azure/azure-sdk-for-js@45f4b2f#diff-d3f158ec5599aa958d5142cf42421faca6b7ab1a0ee5023fa787662406849219
3. constantPaths in package.json [mgmt] Update constantPaths in package.json azure-sdk-for-js#37295