Urtext means something like Original Text. Obviously this is just a concept which by extension means that the Editor is trying to deliver a version that is as close as possible to the original intent of the composer, since in many cases the valid source(s) may be numerous and not even necessarily directly from the hand of the composer, or supervised by the composer. That is particularly true of pieces which are old.
Of course the composer may also have produced more than one version, in which case we get into datation issues to determine which one is the latest revision. Sometimes the revisions are made by hand over the first version, which implies one can determine which one is the oldest.
The original intent of the composer is in many cases difficult to determine precisely and thus lead to decision making based on the editor personal judgement and in light of available materials (manuscripts, editions, practice of the time, copies, letters, testimonies, .....). At the end, there are often more than one valid possibility, in which case the editor will choose one main and indicate variants in the appendix. That said available materials are now well documented and thus most serious modern editors tend to align fairly closely on the content but will differ in the way they present the variants.
For Bach, some of his works were published during his lifetime. It is the case of the partitas for example which he published. In this case obviously the main source is the published version.
But many other pieces were never published, so what we have is manuscript sources, sometimes not even from Bach's hand but copies by various people.
For Invention and Sinfonias, we are lucky as we have what is called a Fair Copy Autograph, which is from Bach's hand and which is in a clean state (ie not a working draft but a clean version obviously in a final form) and we also have an earlier incomplete version included in the Clavier Buchlein. We also have a number of copies for some inventions and sinfonias made by various students which sometimes deviate from the autograph(s) for the notes themselves but mostly for the additional ornaments.
It was a usual practice of the time that composers (except french ones) would not put all the ornaments in the score. Bach was more thorough than most but still, The Inventions and Sinfornias being written for pedagogical purposes, he only indicated most obvious or necessary ornaments and let his students add in the remaining ones as an exercice.
There we get into a difficult question. Should we consider the original text as what Bach left in his latest Fair copy, even though we know that it was expected and customary to add ornaments or should we use the student copies as being representatives of what was played at the time ? Which one would better suit the intent of the composer ?
The approach that all serious modern editors take is to consider the 2 autographs as the main sources (typically thats why we have 2 versions of the Invention 1), simply because we can not decide which particular ornaments Bach would have used. However as it is extremely likely that some of the ornamented copies would be representative of the way it was supposed to be played, these ornaments variants are being indicated in various ways. Some will put them in the score with some mark (smaller or larger fonts, grey color, .....), others will indicate them in the critical commentaries, and in a few cases, you can even find an alternate printed version.
To be noted that there could be a number of possible variants for some pieces. Editors pick usually only a subset of those. Of course you can choose to disagree and make your own ornaments.
So essentially back to your question, is there a consensus. Yes and No and it varies for each piece. For I&S There is a consensus to print the autograph version(s) as the core sources and indicate various ornament variants (serious editors clearly mark out the student variants but other editors just print them without distinction and without comments). There isnt necessarily a consensus on which ornaments to include. There is a fair alignment on some but there are also differences by editor.
Hope it clarifies. At the end it is your musical choice (or your teacher's) based on your experience and knowledge.