By Foo Yun Chee BRUSSELS (Reuters) – U.S. life sciences company Illumina’s offer to cut prices and allow rivals continued access to its technologies has “yet to convince” EU antitrust regulators scrutinising its $8 billion cash-and-stock bid for Grail Inc, people familiar with the matter said. Such doubts could mean that Illumina may have to sweeten its package of proposed remedies if it wants to win EU approval for the acquisition of the cancer detection test maker which it completed last August but is keeping as a separate company prior to regulatory approval. The European Commission decline…