testing: add extra tests to ensure we remove txs correctly

[cmwaters]

Addresses: #1102

this test could be as simple adding an additional check to an existing test that creates square not the max square size, and ensure that each transaction is getting included in the block.

Test_finalizeLayout already includes tests where a non max square size square is created and none of the transactions are dropped so I'm a little confused about this. I've added tests to include that we are dropping transactions if the blobs exceed the square size.

[evan-forbes]

Test_finalizeLayout already includes tests where a non max square size square is created and none of the transactions are dropped so I'm a little confused about this.

hmm good point, I guess that is tested!

[cmwaters]

Shall I close #1102?

[rootulp]

I think the test described in #1102 tests something slightly different. Since the tests in this PR specify a square size, I don't think they are exactly applicable. These tests are contrived (but still useful) because for example in this scenario:

		{
			// only two blob txs should make it in the square
			squareSize:      4,
			nonreserveStart: 4,
			blobTxs: generateBlobTxsWithNIDs(
				t,
				[][]byte{ns1, ns2, ns3},
				[][]int{{2000}, {2000}, {6000}},
			),
			expectedIndexes: [][]uint32{{4}, {8}},
		},

this would keep doubling the square size so that all three blob txs would fit. I think the test for #1102 may want to test PrepareProposal as a whole.