chore(deps): update actions/upload-artifact action to v4 #902

Job	Run time
Publish Charm / Generate the Charm Matrix	2s
Run Tests / Bundle Integration	14m 58s
Run Tests / Individual charm's integration tests (controller)	12m 21s
Run Tests / Individual charm's integration tests (ui)	15m 5s
Run Tests / Lint Code (controller)	20s
Run Tests / Lint Code (ui)	19s
Run Tests / Unit Test (controller)	27s
Run Tests / Unit Test (ui)	28s
Run Tests / Check libraries (jupyter-controller) / Check libraries	24s
Run Tests / Check libraries (jupyter-controller) / Lint	8s
Run Tests / Check libraries (jupyter-ui) / Check libraries	24s
Run Tests / Check libraries (jupyter-ui) / Lint	10s
Publish Charm / Publish Charm (./charms/jupyter-ui)	3m 54s
Publish Charm / Publish Charm (./charms/jupyter-controller)	3m 8s
	52m 8s

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