A state court of appeal rejected the latest effort to upset Proposition 13, California's 1978 property tax-slashing ballot measure. The 1st District Court of Appeal rejected claims by Macy's department store chain that provisions of Proposition 13 are unconstitutional because owners of comparable real estate often pay widely varying property taxes, depending on when the property was purchased. R.H. Macy & Co. and two subsidiaries sued in Contra Costa County Superior Court over the tax bill of the Macy's store at the Sun Valley Mall. Because of a 1986 change of ownership at the store, taxes rose from $44,000 to $117,000 a year, 2.5 times the rate paid by Sears and J.C. Penney at the same mall. A state Court of Appeal in Los Angeles rejected a similar argument two weeks ago.