fix: flakiness on parallel solana-test-validator operation

[aalu1418]

Problem: test flakiness start occurring after upgrading solana image for relay tests

test_helpers_test.go:37: 
        	Error Trace:	/home/runner/work/chainlink-solana/chainlink-solana/pkg/solana/client/test_helpers_test.go:37
        	            				/home/runner/work/chainlink-solana/chainlink-solana/pkg/solana/client/test_helpers_test.go:48
        	Error:      	Received unexpected error:
        	            	rpc call getBalance() on http://127.0.0.1:46261/: Post "http://127.0.0.1:46261/": dial tcp 127.0.0.1:46261: connect: connection refused
        	Test:       	TestSetupLocalSolNode_SimultaneousNetworks
    test_helpers.go:69: 
        	Error Trace:	/home/runner/work/chainlink-solana/chainlink-solana/pkg/solana/client/test_helpers.go:69
        	            				/home/runner/work/chainlink-solana/chainlink-solana/pkg/solana/client/test_helpers_test.go:40
        	            				/home/runner/work/chainlink-solana/chainlink-solana/pkg/solana/client/test_helpers_test.go:48
        	Error:      	Received unexpected error:
        	            	exit status 1
        	Test:       	TestSetupLocalSolNode_SimultaneousNetworks

Solution:

• test validator should point to own directories instead of potentially waiting on the same directory and racing to use/delete it

[cl-sonarqube-production]

Quality Gate failed

Failed conditions
66.7% Coverage on New Code (required ≥ 80%)

See analysis details on SonarQube