fix(components): [upload] add uid for file handleStart

[init-qy]

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closed #9755

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🧪 Playground Preview: https://element-plus.run/?pr=9876
Please comment the example via this playground if needed.

[sxzz]

I think uid will be added here

element-plus/packages/components/upload/src/upload-content.vue

Line 73 in aafdafa

rawFile.uid = genFileId()

[init-qy]

I think uid will be added here

element-plus/packages/components/upload/src/upload-content.vue

Line 73 in aafdafa

rawFile.uid = genFileId()

In this case demo

user use submit method which does not run uploadFiles,

element-plus/packages/components/upload/src/use-handlers.ts

Lines 129 to 133 in aafdafa

	function submit() {
	uploadFiles.value
	.filter(({ status }) => status === 'ready')
	.forEach(({ raw }) => raw && uploadRef.value?.upload(raw))
	}

and this cause the problem

Perhaps we should change the method submit?

[chenxch]

Since pasting does not trigger onStart, the uid can only be added in the modified place, do you have a better solution.

cc @element-plus/backers